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  • Enhancement of mechanical and thermal properties of injection-molded polylactide parts by addition of acrylated epoxidized soybean oil
    Mater. Des. (IF 4.364) Pub Date : 2017-11-20
    L. Quiles-Carrillo, S. Duart, N. Montanes, S. Torres-Giner, R. Balart

    This work reports the effect of acrylated epoxidized soybean oil (AESO) addition on the mechanical, thermal, and thermomechanical properties of polylactide (PLA) parts obtained by injection molding. To this end, AESO, a chemically multi-functionalized vegetable oil, was incorporated into PLA during melt processing. The PLA parts with AESO contents in the 2.5–7.5 wt% range showed a remarkable enhancement in both elongation at break and impact-absorbed energy while their tensile and flexural strength as well as thermomechanical properties were maintained or slightly improved. Additionally, the AESO-containing PLA parts presented higher thermal stability and lower crystallinity. The improvement achieved was ascribed to a dual effect of plasticization in combination with a chain-extension and/or cross-linking process of the PLA chains by the highly reactive acrylate and epoxy groups present in AESO. The use of AESO thus represents an environmentally friendly solution to obtain toughened PLA materials of high interest in, for instance, rigid packaging, automotive or building and construction applications.

    更新日期:2017-11-20
  • Evidence for lattice softening of the Fe-Ga magnetostrictive alloy: Stress-induced local martensites
    Mater. Des. (IF 4.364) Pub Date : 2017-11-20
    Xiaolian Liu, Meixun Li, Junming Gou, Qiaochu Li, Yunhao Lu, Tianyu Ma, Xiaobing Ren

    The over tenfold magnetostriction enhancement by soluting nonmagnetic Ga into body centered cubic (BCC) Fe has been ascribed to crystal lattice softening, which indicates that the Fe-Ga solid solution lies in the crossover of martensitic transformation. Identifying the martensitic phase then becomes essential. Here we report the stress-induced local six-layer modulated monoclinic (6 M) martensites in a Fe79Ga21 alloy solution-treated at 1373 K. Although X-ray diffraction (XRD) and magnetic measurements reveal that the bulk sample exhibits BCC average structure, the transmission electronic microscopy (TEM) characterizations however show that the mechanically grinded foil sample contains local 6 M phase. First principal calculations suggest that low formation energy barrier between the ordered D03 and the 6 M phases are responsible for the stress-induced structural transformation. Our work provides evidence for the lattice softening of Fe-Ga solid solution, adding important insight into understanding the origin of its extraordinary magnetostriction enhancement.

    更新日期:2017-11-20
  • Hf-rich bulk metallic glasses as potential insulating structural material
    Mater. Des. (IF 4.364) Pub Date : 2017-11-16
    A. Lenain, J.J. Blandin, G. Kapelski, F. Volpi, S. Gravier

    Tremendous properties of bulk metallic glasses (BMGs) have led to numerous potential applications in the past few years. An obvious interest has been given to their potential as structural material given their high mechanical properties and their ability to be produced in bulk parts of several millimeters in size. Unlike their crystalline counterparts, they also show very promising insulating properties due to the absence of a periodic lattice. In the present work, the interest of using bulk amorphous metallic alloys as materials combining good structural properties and thermal insulation is discussed. The study of Hf-rich BMGs enables to reduce the thermal losses through a higher σc/κ performance ratio and thus shows very good potential for future insulating and structural applications.

    更新日期:2017-11-20
  • Integration of physically-based and data-driven approaches for thermal field prediction in additive manufacturing
    Mater. Des. (IF 4.364) Pub Date : 2017-11-14
    Jingran Li, Ran Jin, Hang Z. Yu

    A quantitative understanding of thermal field evolution is vital for quality control in additive manufacturing (AM). Because of the unknown material parameters, high computational costs, and imperfect understanding of the underlying science, physically-based approaches alone are insufficient for component-scale thermal field prediction. Here, we present a new framework that integrates physically-based and data-driven approaches with quasi in situ thermal imaging to address this problem. The framework consists of (i) thermal modeling using 3D finite element analysis (FEA), (ii) surrogate modeling using functional Gaussian process, and (iii) Bayesian calibration based on the thermal imaging data. According to heat transfer laws, we first investigate the transient thermal behavior during AM using 3D FEA. A functional Gaussian process-based surrogate model is then constructed to reduce the computational costs from the high-fidelity, physically-based model. We finally employ a Bayesian calibration method, which incorporates the surrogate modeling results and thermal measurements, to enable layer-to-layer thermal field prediction across the whole component. A case study on fused deposition modeling is conducted for components with 7 to 16 layers. The cross-validation results show that the proposed framework allows for accurate and fast thermal field prediction for components with different process settings and geometric designs.

    更新日期:2017-11-15
  • Properties of oriented carbon fiber/polyamide 12 composite parts fabricated by fused deposition modeling
    Mater. Des. (IF 4.364) Pub Date : 2017-11-14
    Guangxin Liao, Zhixiang Li, Yuchuan Cheng, Dingding Xu, Dingchun Zhu, Shenglong Jiang, Jianjun Guo, Xinde Chen, Gaojie Xu, Yuejin Zhu

    This paper reports the thermal and mechanical properties of carbon fiber (CF) reinforced polyamide 12 (PA12) composites for fused deposition modeling (FDM) process. The printable filaments of carbon fiber/PA12 composites with different mass fraction were fabricated and applied in FDM. The results indicate that the tensile strength and flexural strength of 10 wt% CF/PA12 composites are enhanced by 102.2% and 251.1% respectively. The laser-flash diffusivity analysis measurements exhibit remarkable improvements on thermal conductivity (λ) of carbon fiber/PA12 composites. Moreover, the carbon fiber/PA12 composites mechanical properties are greatly improved. Our work presents a kind of anisotropic high performance composite for FDM.

    更新日期:2017-11-15
  • Theoretical, numerical and experimental analysis of three-dimensional double-V honeycomb
    Mater. Des. (IF 4.364) Pub Date : 2017-11-14
    Qiang Gao, Liangmo Wang, Ze Zhou, Z.D. Ma, Chenzhi Wang, Yuanlong Wang

    This paper describes the mechanical properties of the three-dimensional(3D) double-V honeycomb intersected by a two-dimensional double-V structure with negative Poisson's ratio. Considering the effect of the adjacent unit cells, the Poisson's ratio and Young's modulus of the honeycomb under axial loading are derived theoretically. The finite element (FE)model of the 3D double-V honeycomb (DVH) is conducted to verify the theoretical solutions. It is found that the constraint of the adjacent cells does not affect the negative Poisson's ratio but enhance Young's modulus a lot, and the two properties are determined by the stuffer/tensor angles. Then, the prototypes of the 3D DVH is manufactured to carry out the quasi-static experiments. The stiffness and the collapse stress of the theoretical, numerical and experimental solutions are compared, and it is evident that these results agree very well which indicates the analyses of these solutions are convinced. And the quasi-static collapse stress increases with the increment of tensor angle θ1 and the reduction of stuffer angle θ2.

    更新日期:2017-11-15
  • Design and characterisation of a tuneable 3D buckling-induced auxetic metamaterial
    Mater. Des. (IF 4.364) Pub Date : 2017-11-13
    Xin Ren, Jianhu Shen, Phuong Tran, Tuan D. Ngo, Yi Min Xie

    Elastic instability has been increasingly used to design buckling-induced auxetic metamaterials. However, only limited patterns of existing three dimensional (3D) buckling-induced auxetic metamaterials exhibit a reliable 3D auxetic behaviour, i.e., the material will contract along two normal lateral directions under compression along the third direction. In this paper, we study a simple geometrical shape for achieving 3D auxetic behaviour. The unit cell of the proposed 3D design is composed of a solid sphere and three cuboids. Two representative models, one with slender connecting bars and the other with thick connecting bars, are investigated both numerically and experimentally. The results indicate that the designed material with thick connecting bars did not exhibit auxetic behaviour while the one with slender connecting bars did. However, the anticipated 3D auxetic behaviour degraded to a two dimensional (2D) auxetic behaviour, i.e., the material would contract only in one lateral direction and maintain nearly the same dimension in the other lateral direction. This finding was further confirmed by experiments. This research has demonstrated challenges in designing and manufacturing of buckling-induced auxetic metamaterials with 3D auxetic behaviour and highlighted the importance of optimising and fine-tuning the auxetic unit cell using the pattern scale factor.

    更新日期:2017-11-14
  • Titanium anodisation designed for surface colouration - Systemisation of parametric interaction using response surface methodology
    Mater. Des. (IF 4.364) Pub Date : 2017-11-13
    U. Balaji, S.K. Pradhan

    This work statistically examines the influence of operating parameters on the thin oxide layer developed during titanium anodisation and the complexity of parameter interactions on the surface colouration. The optimal parametric combinations for obtaining desired oxide thickness and interference colours are investigated. A three parametric Doehlert experimental design was employed for the purpose. Reliable regression models were developed for oxide thickness (Tmeas), and colour specification viz., lightness (L*) and hue angle (h) with determination coefficients of 0.970, 0.988 and 0.998, respectively. The three chosen parameters namely operating voltage (V), electrolyte concentration (C), and operating temperature (T) were found to have significant interactions during anodisation which are analysed through a response surface. The oxide thickness was found to be influenced by all three parameters. It was additionally found to have multiple optimal parametric combinations for a desirable outcome because of the interactions; the lightness was found to be significantly affected by the interactions of electrolyte concentration and operating temperature; the expected periodicity in hue angle, as reported in literature, persisted amidst parameter interactions with mild variations to the trend. Furthermore, interdependencies were found among the developed regression models.

    更新日期:2017-11-14
  • Anisotropy and heterogeneity of microstructure and mechanical properties in metal additive manufacturing: A critical review
    Mater. Des. (IF 4.364) Pub Date : 2017-11-11
    Y. Kok, X.P. Tan, P. Wang, M.L.S. Nai, N.H. Loh, E. Liu, S.B. Tor

    Metal additive manufacturing (AM) has developed rapidly over the last decade to become a disruptive technology capable of revolutionizing the way that products from various industrial sectors such as biomedical, aerospace, automotive, marine and offshore are designed. Early adopters of the technology like the biomedical and aerospace industries have shown that the better-designed components offer substantial performance improvements over current designs. However, in-depth and comprehensive views on the microstructure and mechanical properties of additively manufactured metals and alloys are less reported. To realize the full design potential that metal AM can offer, especially for load-bearing structural components, it is imperative to provide a thorough understanding on the anisotropic and heterogeneous microstructure and mechanical properties that often occur within metal AM parts. This paper outlines a broad range of metal AM technologies and reviews literatures on the anisotropy and heterogeneity of microstructure and mechanical properties for metal AM parts. It can be highlighted that the contributing factors to the anisotropy and heterogeneity within metal AM parts were either their unique microstructural features or manufacturing deficiencies. Concluding remarks on the state-of-the-art research regarding this topic and the possible solutions to overcome the anisotropy and heterogeneity of metal AM parts are provided.

    更新日期:2017-11-13
  • Non-covalently functionalized graphene strengthened poly(vinyl alcohol)
    Mater. Des. (IF 4.364) Pub Date : 2017-11-11
    Xiaodong Wang, Xianhu Liu, Hongyue Yuan, Hu Liu, Chuntai Liu, Tingxi Li, Chao Yan, Xingru Yan, Changyu Shen, Zhanhu Guo

    In this work, non-covalently functionalized reduced graphene oxide (rGO) reinforced poly(vinyl alcohol) (PVA) nanocomposites were prepared by solution mixing. The agglomeration of graphene sheets was prevented by using surface modifying agent poly(sodium 4-styrenesulfonate) (PSS). The improved mechanical properties, including the Young's modulus and tensile strength of the PVA/rGO nanocomposites compared to neat PVA were attributed to the strong interactions between PVA and rGO such as π–π, hydrogen bonding, and CH–π. A 55% maximum increase in the modulus was obtained by adding only 0.1 wt% rGO, and an increase of 48% in tensile strength was achieved by adding 0.3 wt% rGO. In addition, the thermal properties of the nanocomposites were also improved, which was attributed to the restriction of graphene oxide (GO)/rGO sheets on the chain mobility of polymers on the GO/rGO sheets surface.

    更新日期:2017-11-13
  • A new modified ECM approach on the identification of plastic anisotropic properties by spherical indentation
    Mater. Des. (IF 4.364) Pub Date : 2017-11-11
    Xuepeng Zhan, Jianjun Wu, Hongfei Wu, Mingzhi Wang, Yu Hui, Qi Shang, Yinxiang Ren

    This paper proposes a new approach on the identification of plastic anisotropic properties (σY, n, m), which is based on new modified expanding cavity model (ECM). The new ECM incorporates Hill's an anisotropic yield criterion in 1948 by equivalent transformation of stress expression form from spherical polar coordinate system to space rectangular coordinate system, and considers piling-up or sinking-in effect by introducing volume correction factor t as a semi-theoretical function. Through the indentation analysis for new ECM, the representative stress-strain method can characterize indentation mean pressure and uniaxial flow properties. Meanwhile, nonlinear functional relations between indentation response and plastic anisotropic properties are established. The effectiveness and reliability of new developed ECM approach are verified by the comparisons between identified properties and input properties in spherical indentation simulations, the comparisons between plastic anisotropic properties identified from instrumented indentation experiments and uniaxial compression experiments, and the comparisons between representative flow stress-strain points and compression experimental curves. The identified results are obtained by iterative calculations using the trust-region techniques based on the nonlinear least-square method. Excellent agreement is achieved. Finally, it is demonstrated that the proposed approach is reliable and useful for identification of plastic anisotropic properties of various anisotropic materials.

    更新日期:2017-11-13
  • Hollow ceramic microspheres prepared by combining electro-spraying with non-solvent induced phase separation method: A promising feedstock for thermal barrier coatings
    Mater. Des. (IF 4.364) Pub Date : 2017-11-11
    Fangwei Guo, Xing Chen, Guowei Wang, Zouzhong Hua, Xin Wang, Qin Zhang, Xiaofeng Zhao, Ping Xiao

    Hollow microspheres were prepared by a combination method of electro-spraying and non-solvent induced phase separation, using a slurry of polymer with Y2O3-stabilized ZrO2 powder (YSZ). Subsequent sintering was carried out to obtain porous hollow YSZ microspheres with proper strength aiming to be thermal spraying feedstock. The ESNP particle size and distribution strongly depended on the applied voltage of the electro-spraying process and the jet nozzle diameter. The YSZ microspheres always consisted of a thin spongy shell and highly porous interior structure. The microsphere size decreased from 1000 to 100 μm with increasing voltage (10–20 kV). The cone-jet mode of electrospray reached steady as the nozzle diameter varied from 0.5 to 0.8 mm. Compared with the coatings made from commercial hollow spherical powder, the coatings prepared by ESNP powder had enhanced resistance to sintering and exhibited a longer life than commercial spray powder. It has demonstrated that the ESNP method provides a versatile way to manipulate the microstructure of ceramic microspheres, and could been used to fabricate high performance thermal barrier coatings by plasma spraying.

    更新日期:2017-11-13
  • Flash memory effects and devices based on functional polyimides bearing pendent ferrocene group
    Mater. Des. (IF 4.364) Pub Date : 2017-11-10
    Rui Hao, Nanfang Jia, Guofeng Tian, Shengli Qi, Lei Shi, Xiaodong Wang, Dezhen Wu

    Electron donor-acceptor polyimides (PIs) containing different contents of ferrocene (Fc) as the pendent group, were synthesized for electrical resistive memory device applications. The 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) was employed as the electron-withdrawing monomer to condensation polymerize with the flexible 4,4′-diaminodiphenyl ether (4,4′-ODA), And the electron-donating 4,4′-diamino-4″-ferrocenyltriphenylamine (DAFcTPA) designed to bear the triphenylamine (TPA) and Fc groups. Semiconductor parameter analysis indicates that the synthesized PIs containing no less than 5 mol% of Fc, possess nonvolatile flash memory characteristic with excellent operational stability and transient response to applied voltage. The mechanism related to the electrical switching effect was elucidated through molecular simulation.

    更新日期:2017-11-11
  • Microstructure engineering by dispersing nano-spheroid cementite in ultrafine-grained ferrite and its implications on strength-ductility relationship in high carbon steel
    Mater. Des. (IF 4.364) Pub Date : 2017-11-10
    C. Prasad, P. Bhuyan, C. Kaithwas, R. Saha, S. Mandal

    Thermo-mechanical processing is performed to engineer the microstructure comprising of nano-spheroidized cementites in ultrafine-grained ferrite in high carbon steel to enhance strength-ductility relationship. Spheroidization is achieved through heavy warm rolling (4-passes of 30% reduction at 823 K and 873 K) followed by extended annealing (1 h and 2 h) at the respective deformation temperatures. The influence of annealing temperature and time on the evolution of carbide precipitates, the extent of periodization and ferrite softening is investigated employing scanning electron microscopy, electron back scatter diffraction and transmission electron microscopy techniques. A near-complete spheroidization is achieved following heavy warm rolling and subsequent annealing for 2 h at 873 K (WR873K-2H). Although ferrite grain size increases with time and temperature of annealing, it ceases to cross the ultrafine regime (470–750 nm) due to the pinning effect of the carbides that restricts the migration of ferrite grain boundaries. A simultaneous increase in strength and ductility is achieved following heavy warm rolling and subsequent annealing for 1 to 2 h at 873 K. Maximum elongation (~ 30%) is achieved in the WR873-2H specimen in contrast to ~ 20% elongation in as-received specimen. Such an increase in ductility is due to the near-complete spheroidization as revealed by the ductile mode of fracture in fractrographic analysis.

    更新日期:2017-11-11
  • Role of Mn and Cr on structural parameters and strain energy during FCC-HCP martensitic transformation in Fe-Mn-Cr shape memory alloys
    Mater. Des. (IF 4.364) Pub Date : 2017-11-10
    F. Malamud, L.M. Guerrero, P. La Roca, M. Sade, A. Baruj

    Fe-Mn-based alloys show the shape memory effect which is mainly related to the FCC-HCP martensitic transformation. Cr is one of the additional elements which improve the properties of these alloys. In the present work structural data are obtained for the FCC austenite, and both martensitic structures, HCP and BCC, for an extended composition range where the FCC-HCP transition takes place. Lattice parameters are determined by X-Ray diffraction measurements performed at room temperature. The volume change between the austenite and each martensitic structure plays a significant role on relevant properties for martensitic transformations, like the strain energy associated to the transition. The effect of Mn and Cr on lattice parameters and volume change between FCC and HCP is determined and modeling of the data is presented. This result allows estimating the strain energy associated to the phase change. By using this information, the strain energy contribution to the balance of energy for the HCP nucleation is discussed. The addition of Cr decreases the volume change between FCC and HCP for contents larger than 12 wt% Cr which leads to a decrease of the strain energy. Both effects favor an increased shape memory effect associated to the FCC-HCP martensitic transition.

    更新日期:2017-11-11
  • Synergistic antibacterial activity of multi components in lysozyme/chitosan/silver/hydroxyapatite hybrid coating
    Mater. Des. (IF 4.364) Pub Date : 2017-11-10
    Wu-Zhong Yu, Yanzhe Zhang, Xiangmei Liu, Yiming Xiang, Zhaoyang Li, Shuilin Wu

    A hybrid coating composed of lysozyme (Lys), chitosan (CS), silver (Ag), and hydroxyapatite (HAp) was constructed on Ti implant to endow this material with highly effective antibacterial activity and biocompatibility through a two-step method. Firstly, CS/Ag/HAp was fabricated on the surface of Ti by electrochemical deposition. Secondly, CS/Ag/HAp was covered by Lys film via spin-coating process in order to further improve the antibacterial efficiency without increasing the content of Ag. X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were employed to investigate the phase formation, surface morphologies and microstructure of the hybrid coatings. Results showed that the as-prepared coating had a hierarchical nanostructure with a uniform distribution of Lys, CS, Ag and HAp. The in vitro antibacterial and cell culture tests revealed that this hybrid coating of Lys/CS/Ag/HAp could not only endow Ti with much higher self-antibacterial efficacy of over 95.28% and 98.02% in 12 h, and still remain sufficiently efficiency of 95.42% and 97.46% after 5 days against Escherichia coli and Staphylococcus aureus, respectively, but also almost be non-cytotoxic. These results suggested that Lys/CS/Ag/HAp-Ti could be a promising biocompatible surface system for metallic implants to resist the bacterial infection for a long time.

    更新日期:2017-11-11
  • Study of microstructure, mechanical properties and residual stresses in full penetration electron beam welded Ti-5Al-2.5Sn alloy sheet
    Mater. Des. (IF 4.364) Pub Date : 2017-11-09
    Massab Junaid, Fahd Nawaz Khan, Nabi Baksh, Mirza Nadeem Baig, Khalid Rahman

    Protection of the molten pool from gaseous contamination has always been of prime importance in welding of titanium alloys. A vacuum environment in electron beam welding serves this purpose and eliminates the use of shielding gas during the joining process. However, this may lead to variation in microstructure, mechanical properties, residual stress distribution and distortions compared to the widely used laser and TIG welding operations. In the present work, EBW was used to weld Ti-5Al-2.5Sn alloy sheet with welding current ranging from 14 mA to 20 mA. Owing to vacuum environment, oxygen contents in the fusion zone were very low for all the welding currents. However, welding current had a significant influence on the weld pool width, micro-hardness and grain size in the FZ. A complete martensitic transformation was not observed in the FZ at any of the welding currents used. Furthermore, maximum residual stresses upto 280 MPa (compressive) and 320 MPa (tensile) were found in the longitudinal direction near the weld centerline. The measured high residual stresses, distortions and partial martensitic transformations in FZ were attributed to a reduced cooling rate due to the absence of shielding gas in electron beam welding.

    更新日期:2017-11-10
  • Influence of multi-beam preheating temperature and stress on the buckling distortion in electron beam welding
    Mater. Des. (IF 4.364) Pub Date : 2017-11-09
    Wei Zhang, Hang Fu, Jikang Fan, Renjie Li, Haiying Xu, Fangjun Liu, Bojin Qi

    In order to decrease the buckling distortion of thin-walled structures, a new electron beam welding method with simultaneous multi-beam preheating on both sides of the weld is proposed. Compared with traditional electron beam welding, this method can effectively reduce welding distortion, without the use of auxiliary clamping fixtures or post-weld heat treatment. In the finite element analysis, the conical Gaussian heat source model was selected as the heat source for welding and the rectangle uniform plane heat source model was selected as the heat source for multi-beam preheating. The temperature distribution, thermal stress and welding distortion of welded SUS304 stainless steel sheets were simulated and a series of experiments were conducted to verify the feasibility of electron beam welding with multi-beam preheating. Experiment and simulation results show that the temperature distribution with multi-beam preheating is more uniform and thermal tensioning effect caused by multi-beam preheating can reduce the compressing stress in the welding zone. Therefore, the application of multi-beam preheating method can reduce the plastic compressing deformation and final buckling distortion of thin-walled structures. Using this method, maximal 80% reduction of the buckling distortion can be achieved.

    更新日期:2017-11-10
  • Prediction of residual stress within linear friction welds using a computationally efficient modelling approach
    Mater. Des. (IF 4.364) Pub Date : 2017-11-08
    Clément Bühr, Bilal Ahmad, Paul A. Colegrove, Anthony R. McAndrew, Hua Guo, Xiang Zhang

    Modelling the mechanical mixing occurring at the interface of a linear friction weld (LFW) is complex, making it difficult to study the development of residual stresses within real engineering workpieces. To address this, a sequentially-coupled numerical model of a Ti-6Al-4V LFW was developed, bypassing the modelling of the oscillations by applying the heat at the weld interface and sequentially removing rows of elements to account for the burn-off. Increasing the rubbing velocity was found to numerically increase the peak of residual stress while narrowing the distribution. Only small changes arose from increasing the applied pressure or changing the oscillation direction. Predictions suggested a strong correlation between the phase 3 temperature profile and the residual stress field subsequently created. Validation against neutron diffraction and contour method are also presented. This approach provides a computationally efficient technique to study the residual stress development within large 3D structures.

    更新日期:2017-11-10
  • Toughening of nanocelluose/PLA composites via bio-epoxy interaction: Mechanistic study
    Mater. Des. (IF 4.364) Pub Date : 2017-11-07
    Xiangtao Meng, Vera Bocharova, Halil Tekinalp, Shiwang Cheng, Alexander Kisliuk, Alexei P. Sokolov, Vlastimil Kunc, William H. Peter, Soydan Ozcan

    While PLA possesses modest to good strength and stiffness, broader application is hindered by its brittle nature. The aim of this study was to develop strong and tough polymeric materials from renewable biomaterials and understand the underlying interactions and mechanisms. Cellulose nanofibrils (CNFs) and epoxidized soybean oil (ESO) were compounded with poly(lactic acid) (PLA) to create a PLA-CNF-ESO tertiary nanocomposite system. Tensile and dynamic mechanical analyses were performed to see how variations in ESO and CNF content affect mechanical properties such as strength, modulus, ductility, and toughness. It was found that at low CNF levels (10 wt%) the addition of ESO can improve the ductility of the nanocomposites 5- to 10-fold with only slight losses in strength and modulus, while at higher CNF levels (20 and 30 wt%), ESO exhibited little effect on mechanical properties, possibly due to percolation of CNFs in the matrix, dominating stress transfer. Therefore, it is important to optimize CNF and ESO amounts in composites to achieve materials with both high strength and high toughness. Efforts have been made to understand the underlying mechanisms of the mechanical behavior of one class of these composites via thermal, dynamic mechanical, rheological, morphological, and Raman analyses.

    更新日期:2017-11-10
  • Fabrication of hydrophilic and oil-repellent surface via CF4 plasma treatment
    Mater. Des. (IF 4.364) Pub Date : 2017-11-06
    Shusen Peng, Yongcun Ma

    Special wetting surface with hydrophilic and oil-repellent characteristic is successfully prepared by treating hydrophilic PEGylated surface with CF4 plasma. Wettability and structure of the modified PEGylated polymer surfaces are investigated by contact angle (CA) measurements and X-ray photoelectron spectroscopy (XPS). The results of contact angle measurements show that water CA and hexadecane CA have different dependences with CF4 plasma treating time. After a 5 min treatment with CF4 plasma, the difference between water and oil CA reaches a maximum value on the modified PEGylated surface, wherein water and oil CA is 30.7° and 60.7°, respectively. We believe the technique can be further used for construction of textiles with anti-contamination and easy-decontamination properties.

    更新日期:2017-11-10
  • High-quality graphene directly grown on Cu nanoparticles for Cu-graphene nanocomposites
    Mater. Des. (IF 4.364) Pub Date : 2017-11-06
    Shuangyue Wang, Shaobo Han, Guoqing Xin, Jianliang Lin, Ronghua Wei, Jie Lian, Kai Sun, Xiaotao Zu, Qingkai Yu

    High-quality graphene was directly grown on the surface of Cu nanoparticles (NPs) via chemical vapor deposition (CVD) and then the graphene-covered Cu NPs were consolidated into dense Cu-graphene nanocomposites at different temperature. The surface of Cu NPs is well protected from oxidation due to the coverage of graphene. Nanocomposite consolidated at 650 °C (Cu/G-650) exhibits a hardness of 2.53 GPa with no distinctive different electrical resistivity compared with pure Cu, 2 orders of magnitude decrease in wear rate and 175% improvement in the coefficient of friction (COF) were reported for the Cu/G-650 nanocomposite as compared with pure Cu. The formation of graphene tribofilm is attributed for the effective protection of the Cu matrix from wear.

    更新日期:2017-11-10
  • Mapping of magnetic and mechanical properties of Fe-W alloys electrodeposited from Fe(III)-based glycolate-citrate bath
    Mater. Des. (IF 4.364) Pub Date : 2017-11-05
    A. Nicolenco, N. Tsyntsaru, J. Fornell, E. Pellicer, J. Reklaitis, D. Baltrunas, H. Cesiulis, J. Sort

    Electrodeposition of Fe-W coatings has been carried out from an environmentally friendly Fe(III)-based glycolate-citrate bath. Samples with tungsten content from 6 to 25 at.% were electrodeposited in a controlled way by changing electrodeposition parameters: current density, pH, and temperature. X-ray diffraction analysis showed that the structure of Fe-W coatings transforms from nanocrystalline to amorphous-like as the W content increases and the crystallite size reduces below 10 nm. However, the peculiarities of the structural transitions are linked not only with the W content. Deposition temperature plays a crucial role, due to the different activation energy of crystallization. Following the direct Hall–Petch relation, a maximum hardness of ~ 10 GPa was found for the alloy with the highest W content, making it comparable to that of electrolytic chromium. The Fe2W intermetallic compound forms at higher W concentration as proven by Mössbauer spectroscopy, and contributes to the increased hardness of these alloys. The alloys retain a soft magnetic character within a wide compositional range, although increasing the W content leads to a reduction of the saturation magnetization. Fe-12 at.% W coatings show an optimum combination of mechanical and magnetic properties, thus making these newly developed coatings appealing environmentally-friendly alternative materials for multi-scale technologies.

    更新日期:2017-11-10
  • Recovery stress formation in FeMnSi based shape memory alloys: Impact of precipitates, texture and grain size
    Mater. Des. (IF 4.364) Pub Date : 2017-11-04
    A. Arabi-Hashemi, W.J. Lee, C. Leinenbach

    FeMnSi based shape memory alloys are considered for engineering applications such as prestressing of concrete or coupling devices. For this, a high recovery stress is desired which forms when the FeMnSi alloy is first elongated and then heated above the austenite transformation temperature under mechanical constraints. In this work, we study the impact of three different microstructural properties on the recovery stress of Fe17Mn5Si10Cr4Ni1(V,C) shape memory alloys: Precipitates, texture and grain size. Precipitates allowed varying the recovery stress in a broad range between 255 MPa and 564 MPa. A recovery stress of 564 MPa was achieved by a combination of a high materials yield strength σ0.1of 536 MPa and a shape recovery of 14%. The [001] grain orientation with a low Schmid factor has a beneficial impact on the recovery stress due to a higher yield strength when compared with the [011] orientation. A decrease of the grain size caused a Hall-Petch strengthening but had no influence on the recovery stress. However the pseudo-elasticity increased for a decrease of grain size.

    更新日期:2017-11-10
  • Rapid and partial crystallization to design ductile CuZr-based bulk metallic glass composites
    Mater. Des. (IF 4.364) Pub Date : 2017-11-04
    K.K. Song, X.L. Han, S. Pauly, Y.S. Qin, K. Kosiba, C.X. Peng, J.H. Gong, P.X. Chen, L. Wang, B. Sarac, S. Ketov, M. Mühlbacher, F. Spieckermann, I. Kaban, J. Eckert

    Transformation-induced plasticity in CuZr-based bulk metallic glass (BMG) composites opens up a new perspective for the design of ductile BMG composites. In this work, rapid and partial crystallization of BMGs is proposed to tailor microstructures of ductile BMG composites. During the early crystallization stage, the precipitation of B2 CuZr crystals in the Cu42Zr42Al10Co6 BMGs is growth-controlled at low or high heating rates after having passed through a nucleation-dominated temperature region. Abundant nucleation is beneficial for the uniform precipitation of B2 crystals in the glassy matrix. Compared with annealing processes at slow heating, the degree of the free volume annihilation could be reduced to some content by employing a high heating rate. The microstructures of CuZr-based BMG composites can be effectively tuned by changing rapid annealing parameters, which enhances the ductility of the resulting BMG composites. This approach proves to be efficient for the development of ductile metastable alloys and composites.

    更新日期:2017-11-10
  • Microsphere lithography for scalable polycrystalline diamond-based near-infrared photonic crystals fabrication
    Mater. Des. (IF 4.364) Pub Date : 2017-11-03
    Mária Domonkos, Marián Varga, Lukáš Ondič, Lenka Gajdošová, Alexander Kromka

    We demonstrate the fabrication of a polycrystalline diamond-based two-dimensional photonic crystal (PhC) slab using microsphere lithography (MSL). First, the essential issues of MSL on rough diamond surfaces are demonstrated. The peak-to-valley value of the rough surfaces is shown as the most important parameter in choosing the appropriate sphere size for the MSL technique. Second, we fabricate a diamond-based PhC composed of a hexagonal lattice of air holes and tuned to have a leaky mode in the near-infrared wavelength region at 1.31 μm which is an important telecommunication window. A monolayer of plasma-treated polystyrene microspheres with controllable size and periodicity, combined with a metal mask, are utilised as templates in the fabrication process. The prepared diamond films and photonic crystal are characterised using scanning electron microscopy, atomic force microscopy, Raman spectroscopy, reflection, and transmission measurements. In order to investigate the optical properties of the PhC, the experimental measurements are compared with simulation outputs. The successful employment of MSL on rough diamond films with their unique properties opens the road to the large scale fabrication of highly durable and chemically inert scalable structures.

    更新日期:2017-11-10
  • Experimental and numerical study on soft-hard-soft (SHS) cement based composite system under multiple impact loads
    Mater. Des. (IF 4.364) Pub Date : 2017-10-31
    Jun Wu, Xuemei Liu, Hongyuan Zhou, Liang Li, Zhongxian Liu
    更新日期:2017-11-01
  • 更新日期:2017-11-01
  • Drug release, cytocompatibility, bioactivity, and antibacterial activity of doxycycline loaded Mg-Ca-TiO2 composite scaffold
    Mater. Des. (IF 4.364) Pub Date : 2017-10-31
    H.R. Bakhsheshi-Rad, E. Hamzah, Mark P. Staiger, George J. Dias, Z. Hadisi, M. Saheban, M. Kashefian
    更新日期:2017-11-01
  • Model for predicting fatigue life and limit of steels based on micromechanics of small crack growth
    Mater. Des. (IF 4.364) Pub Date : 2017-10-31
    Kazuki Shibanuma, Koya Ueda, Hiroaki Ito, Yoshiki Nemoto, Masao Kinefuchi, Katsuyuki Suzuki, Manabu Enoki
    更新日期:2017-11-01
  • 3-Dimensional inkjet printing of macro structures from silver nanoparticles
    Mater. Des. (IF 4.364) Pub Date : 2017-10-31
    Jayasheelan Vaithilingam, Ehab Saleh, Lars Körner, Ricky D. Wildman, Richard J.M. Hague, Richard K. Leach, Christopher J. Tuck
    更新日期:2017-11-01
  • Effect of vanadium doping on ZnO sensing properties synthesized by spray pyrolysis
    Mater. Des. (IF 4.364) Pub Date : 2017-10-31
    Zahira El khalidi, Elisabetta Comini, Bouchaib Hartiti, Abderrahim Moumen, Hashitha M.M. Munasinghe Arachchige, Salah Fadili, Philippe Thevenin, Abderrafi Kamal
    更新日期:2017-11-01
  • Characterisation of epoxy powders for processing thick-section composite structures
    Mater. Des. (IF 4.364) Pub Date : 2017-10-26
    James M. Maguire, Kapileswar Nayak, Conchúr M.Ó. Brádaigh
    更新日期:2017-10-27
  • Low-density microcellular carbon foams from sucrose by NaCl particle templating using glycerol as a plasticizing additive
    Mater. Des. (IF 4.364) Pub Date : 2017-10-26
    Praveen Wilson, Sujith Vijayan, K. Prabhakaran
    更新日期:2017-10-26
  • High-temperature wettability and interactions between Hf-containing NbSi-based alloys and Y2O3 ceramics with various microstructures
    Mater. Des. (IF 4.364) Pub Date : 2017-10-25
    Beibei Wan, Huarui Zhang, Ming Gao, Peng Bai, Hu Zhang
    更新日期:2017-10-26
  • Loose yarn of Ag-ZnO-PAN/ITO hybrid nanofibres: Preparation, characterization and antibacterial evaluation
    Mater. Des. (IF 4.364) Pub Date : 2017-10-25
    Yuefan Wei, Yong Bing Chong, Hejun Du, Junhua Kong, Chaobin He
    更新日期:2017-10-25
  • Novel volumetric Helmholtz free energy function accounting for isotropic cavitation at finite strains
    Mater. Des. (IF 4.364) Pub Date : 2017-10-24
    M. Drass, J. Schneider, S. Kolling
    更新日期:2017-10-25
  • On the evolution of substrate's residual stress during cold spray process: A parametric study
    Mater. Des. (IF 4.364) Pub Date : 2017-10-24
    Bahareh Marzbanrad, Hamid Jahed, Ehsan Toyserkani
    更新日期:2017-10-25
  • High bio-content polyurethane (PU) foam made from bio-polyol and cellulose nanocrystals (CNCs) via microwave liquefaction
    Mater. Des. (IF 4.364) Pub Date : 2017-10-21
    Xingyan Huang, Cornelis F. De Hoop, Jiulong Xie, Qinglin Wu, Dorin Boldor, Jinqiu Qi
    更新日期:2017-10-23
  • Self-assembly of stearic acid into nano flowers induces the tunable surface wettability of polyimide film
    Mater. Des. (IF 4.364) Pub Date : 2017-10-21
    Chang-Lian Xu, Yu-Zhong Wang
    更新日期:2017-10-23
  • Out-of-plane compression of Ti-6Al-4V sandwich panels with corrugated channel cores
    Mater. Des. (IF 4.364) Pub Date : 2017-10-19
    Zhen-yu Zhao, Bin Han, Xin Wang, Qian-cheng Zhang, Tian Jian Lu
    更新日期:2017-10-20
  • Structural signature and size-dependent mechanical response of frozen-in icosahedral phase in bulk metallic glasses
    Mater. Des. (IF 4.364) Pub Date : 2017-10-19
    Hye Jung Chang, Hyun Seok Oh, Je In Lee, Eun Soo Park
    更新日期:2017-10-19
  • Direct diffusion bonding of immiscible tungsten and copper at temperature close to Copper's melting point
    Mater. Des. (IF 4.364) Pub Date : 2017-10-19
    Jie Zhang, Yuan Huang, Yongchang Liu, Zumin Wang
    更新日期:2017-10-19
  • Materials selection of flexible open-cell foams in energy absorption applications
    Mater. Des. (IF 4.364) Pub Date : 2017-10-18
    Evan T. Bird, Anton E. Bowden, Matthew K. Seeley, David T. Fullwood
    更新日期:2017-10-19
  • Reactive extrusion preparation and characterization of canola meal composites reinforced by a novel polymeric chain extender
    Mater. Des. (IF 4.364) Pub Date : 2017-10-18
    Shuzhao Li, Kristi Ciardullo, Elizabeth Donner, Michael R. Thompson, Curtis Rempel, Qiang Liu
    更新日期:2017-10-19
  • Reinforcing 3D printed acrylonitrile butadiene styrene by impregnation of methacrylate resin and cellulose nanocrystal mixture: Structural effects and homogeneous properties
    Mater. Des. (IF 4.364) Pub Date : 2017-10-18
    Xinhao Feng, Zhaozhe Yang, Sahar S.H. Rostom, Mark Dadmun, Siqun Wang, Qingwen Wang, Yanjun Xie
    更新日期:2017-10-18
  • 更新日期:2017-10-18
  • 2D magnetic domain wall ratchet: The limit of submicrometric holes
    Mater. Des. (IF 4.364) Pub Date : 2017-10-17
    J. Herrero-Albillos, C. Castán-Guerrero, F. Valdés-Bango, J. Bartolomé, F. Bartolomé, F. Kronast, A. Hierro-Rodriguez, L.M. Álvarez Prado, J.I. Martín, M. Vélez, J.M. Alameda, J. Sesé, L.M. García
    更新日期:2017-10-17
  • Densification behavior, microstructural evolution, and mechanical properties of TiC/316L nanocomposites fabricated by selective laser melting
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Bandar AlMangour, Dariusz Grzesiak, Tushar Borkar, Jenn-Ming Yang
    更新日期:2017-10-17
  • Axon mimicking hydrophilic hollow polycaprolactone microfibres for diffusion magnetic resonance imaging
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Feng-Lei Zhou, Zhanxiong Li, Julie Gough, Penny L. Hubbard Cristinacce, Geoff J.M. Parker
    更新日期:2017-10-17
  • Anisotropic Ti-6Al-4V gyroid scaffolds manufactured by electron beam melting (EBM) for bone implant applications
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Arash Ataee, Yuncang Li, Darren Fraser, Guangsheng Song, Cuie Wen
    更新日期:2017-10-16
  • 3D-printed bioabsordable polycaprolactone stent: The effect of process parameters on its physical features
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Antonio J. Guerra, Joaquim Ciurana
    更新日期:2017-10-16
  • Oxidation–nitridation-induced recrystallization in a near-α titanium alloy
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Tomonori Kitashima, Toru Hara, Yang Yang, Yuka Hara
    更新日期:2017-10-16
  • Hierarchically porous composites fabricated by hydrogel templating and viscous trapping techniques
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Benjamin R. Thompson, Tommy S. Horozov, Simeon D. Stoyanov, Vesselin N. Paunov
    更新日期:2017-10-16
  • Surface quality improvement of selective laser sintered polyamide 12 by precision grinding and magnetic field-assisted finishing
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Guo Jiang, Bai Jiaming, Liu Kui, Wei Jun
    更新日期:2017-10-16
  • Controllable hierarchical micro/nano patterns on biomaterial surfaces fabricated by ultrasonic nanocrystalline surface modification
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Yuan Lian, Haifeng Qin, Nitin Mehra, Jiahua Zhu, Zhengnan Yang, Gary L. Doll, Chang Ye, Yalin Dong
    更新日期:2017-10-16
  • High temperature fatigue characteristics of P/M and hot-forged W-Re and TZM for X-ray target of CT scanner
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Mohd Azhar Harimon, Yukio Miyashita, Yuichi Otsuka, Yoshiharu Mutoh, Shinichi Yamamoto
    更新日期:2017-10-16
  • Strain rate-induced plasticity in bcc β-Ti alloy single crystal micropillars containing brittle ω-precipitates
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Wei Chen, Zaiwang Huang, Shuo Cao, Yan Pan, Mingda Huang, Qingmiao Hu, Ding Xu, Qiaoyan Sun, Lin Xiao, Jun Sun
    更新日期:2017-10-16
  • Nano-scale precipitation and phase growth in Mg-Gd binary alloy: An atomic-scale investigation using HAADF-STEM
    Mater. Des. (IF 4.364) Pub Date : 2017-10-16
    Jingxu Kent Zheng, Ruichun Luo, Xiaoqin Zeng, Bin Chen
    更新日期:2017-10-16
  • Carbon nanotubes as a unique agent to fabricate nanoceramic/metal composite powders for additive manufacturing
    Mater. Des. (IF 4.364) Pub Date : 2017-10-14
    Weiwei Zhou, Xiaohao Sun, Keiko Kikuchi, Naoyuki Nomura, Kyosuke Yoshimi, Akira Kawasaki
    更新日期:2017-10-14
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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