ABSTRACT The Al-Si-Cu-Mg-Ni alloy is a commonly used piston alloy. In this work, different amounts of phosphorus modifier and Al-2P (Al-2%P) master alloy modifier were added to the original alloy. The ultrasonic melt treatment method was also applied to improved the microstructure of near-eutectic multi-cast Al–Si alloys. Investigation was performed by means of optical microscopy and scanning electron

ABSTRACT Microstructural changes due to 160 MeV oxygen ion irradiation on pure Nb have been characterised using X-ray Diffraction Line Profile Analyses. Microstructural parameters such as coherent domain size, microstrain within the domain and dislocation density are evaluated from the homogeneously damaged region. It is observed that the domain size decreases along with an increase in microstrain

ABSTRACT To be used as a new kind of three-dimensional printing material, rheological behaviour of a La-based bulk metallic glass (BMG) was studied over a wide range of high temperatures and strain rates by uniaxial compression experiments. The variations in peak stress and steady stress with temperature and strain rate were analysed. Three rheological regions were revealed for the BMG: a non-Newtonian

ABSTRACT Multi-scale Al7Cu2Fe and AlFeCu phases are formed in Al-Zn-Mg-Cu-Fe alloys after thermomechanical processing. These multi-scale particles significantly affect the size, morphology, and orientation of recrystallised grains and their corresponding mechanical properties. With increasing concentrations of iron-rich phase particles, the grain size in alloys is significantly reduced from 29.3 μm

ABSTRACT This study investigates heterogeneity in the deformation of an annealed sheet of commercially pure titanium (cp-Ti), its variation with loading direction and its influence on dwell fatigue response. Cp-Ti sheet with a typical cold rolling texture was deformed, along its rolling direction (RD) and transverse direction (TD), to the same strain level in tension. Higher level of grain boundary

ABSTRACT The Portevin–Le Chatelier effect in an AlCu/Al 2O 3 composite with a large volume fraction (60%) of ceramic particles is investigated from a numerical point of view using a strain-ageing visco-plastic material model for the metallic matrix and several different finite element meshes based on real microstructures. Even for this very large volume fraction, some serrations are observed on the

ABSTRACT Thermodynamic models based on the Landau free-energy density are popular and well suited to study the phase transition properties of ferroelectric and antiferroelectric liquid crystals. Ferroelectric and antiferroelectric liquid crystals have molecular chirality which play an important role in the technology of liquid crystals for the application of devices performance. The structural properties

ABSTRACT Despite decades of intensive rehearses, we still lack robust and physically clear methods to discover new metallic alloys with high glass-forming ability (GFA). Different empirical criteria proposed to estimate GFA have limited applicability. Here we address the impact of thermodynamic and geometric factors on GFA of Ni-Zr-Al alloys. Using the ideal associated solution model, we calculated

ABSTRACT In the present works, we numerically study the persistent current of a quantum ring systems in the presence of charged rods and impurities. Effects of inner ring radius, ring thickness, negatively and positively charged rods radial electric fields, charged rod position, donor and acceptor impurities, and their positions, on the persistent current have been thoroughly investigated. In addition

ABSTRACT In this research, transient liquid phase (TLP) bonding of IN718 and SS316L dissimilar alloys was carried out using MBF-20 amorphous interlayer. The effects of bonding temperature and time ranging from 1030°C to 1110°C and 1–30 min on the microstructure and mechanical properties of the bonded samples were studied. The mechanism of the microstructure formation and the solidification sequence

ABSTRACT We investigate the formation and stabilisation of magnetic skyrmions defined on a ferromagnetic square lattice Heisenberg model in the presence of single ion anisotropy. By means of Monte Carlo simulations, we show in the absence of magnetic anisotropy that for the ground state and finite temperature region, the present model exhibits spiral, skyrmion lattice and field polarised phases in

ABSTRACT Indentation scaling relationships intend to guide indentation experiments and help understand the indentation hardness. In the present study, dimensionless functions were obtained by fitting a series of numerical results of the cross-scale indentation tests based on a strain gradient plasticity theory. The closed-form indentation scaling relationships were found between dimensionless material

ABSTRACT Confined geometries offer useful and experimentally amenable mechanical testing arrangements in which to study the molecular and micro-structural processes which govern plastic yield in stress environments dominated by hydrostatic pressure over shear. However, the changes to macroscopic stress – strain behaviour that result from switching from an unconfined mode such as uniaxial compression

ABSTRACT Pop-in is a widely observed phenomenon in nanoindentation. In this paper, dislocation evolution in pop-in processes is analysed in detail through molecular dynamics (MD) simulations. We found that a large number of dislocations nucleate homogeneously at the initiation of pop-in, followed by extensive dislocation propagation, which is the dominant mode of plastic deformation during pop-in.

ABSTRACT The present work has examined the influence of strain path change on the deformation behaviour, texture evolution and recrystallisation process in an extruded pure magnesium. The samples were compressed at room temperature along ED, ND and ND–ED directions to the same total strain. Electron back-scattered diffraction (EBSD), hardness testing and X-ray diffraction were utilised to examine the

ABSTRACT The excess free energies of sub-binary Al–Sn, Sn–Zn and Zn–Al alloys and ternary Al–Sn–Zn alloy were computed using the optimised exponential parameters of R–K polynomial at 973, 1073, 1173 and 1273 K. The computed values of free energy of mixing, enthalpy of mixing and activity of the ternary alloy were compared with the available experimental data. The surface concentrations of the monomers

ABSTRACT The heat capacity and magnetisation of the obtained by the solid-phase method from simple oxides single-phase compound Ba2FeMoO6-δ, in which the superstructural ordering of Fe and Mo cations occurs, was studied. The anomalous behaviour of the temperature dependences of heat capacity (deviation from Debye T3 law) and magnetic moment (ZFC mode) is interpreted as the existence of a superparamagnetic

ABSTRACT The equilibration of a trivalent polygonal network in two dimensions (2D) is a universal phenomenon in nature, but the underlying mathematical mechanism remains unclear. In this study, a relaxation algorithm based on a simple geometrical rule was developed to simulate the equilibration. The proposed algorithm was implemented using the Python programming language. The simulated relaxation changed

ABSTRACT The study of lattice mechanical properties of transition metals using pseudopotential is burdensome as the presence of d-band in these metals complicates their electronic structure. The use of pseudopotential for the study of physical properties can be justified if it accounts for the effect of d-band. The local form of the pseudopotentials is widely used to study the physical properties of

ABSTRACT Heusler compounds exhibit a wide range of properties for both fundamental and potential technological interests. The extensive tunability of the Heusler compounds, through chemical substitutions and structural motifs, makes the family specifically interesting. As the maturity of these materials grows and commercial applications become more near-term, the properties of these materials become

ABSTRACT First-principles calculations were performed to study the structural, mechanical, electronic and magnetic properties of Fe(8−x)MoxB4 (x = 0, 0.25, 0.5, 1, 2, 3, 4, 5, 6, 7, 8). Results show that the Mo atoms would enter the Fe2B lattice by replacing the Fe atoms and cause a change in the crystal structure. According to the calculated formation enthalpy, all borides are thermodynamically stable;

ABSTRACT The role of shear strain and deformation temperature on the microstructure and texture evolution in commercially pure (CP) titanium was investigated in the present study. CP titanium samples were subjected to free-end torsion at elevated temperatures, starting from room temperature (298 K) to 873 K, for different shear strains of 0.5–2.5. Deformation twins of {10 1¯2} type were observed in

ABSTRACT Modeling cluster dynamics or rate theory to describe the microstructural evolution of irradiated materials requires a precise knowledge of the migration energy of a self-interstitial atom (SIA), a product of energetic particle radiation. We measured the evolution of the number density of SIA clusters in electron-irradiated α-iron at low temperatures (110–320 K) by in situ observation using

ABSTRACT The shear of a crystalline interface by a matrix dislocation is an elementary phenomenon of plasticity that generates a three-dimensional elastic field difficult to express. However, in the case of a flat interface and two elastic isotropic media, the present work shows that this field can be described starting from an explicit form of the Green tensor associated with a point force exerted

ABSTRACT A duplex treatment, namely, plasma carbonitriding followed by multi-arc ion plating, was used to improve the high-temperature tribological properties of TiAlCrN coatings on 300M steel in this research. The carbonitriding layer was first prepared on 300M steel substrates by the double glow plasma metallization technique. A corresponding heat treatment was performed, and then the TiAlCrN coating

ABSTRACT Atom probe tomography (APT) and selected area electron diffraction (SAED) by transmission electron microscopy (TEM) were applied to nano-scale precipitates formed in a neutron-irradiated iron (99.99% pure) at high temperatures. In the conventional TEM, we discovered donut-type precipitates on the {100} planes that formed at the dilatational side of interstitial type dislocation loops with

ABSTRACT It is well known that cracks are observed on the surface without load when pure nickel is left in ambient air after hydrogen charge. It has been due to the decomposition of nickel hydride generated during hydrogen charging. In the present work, microcracks were investigated at the surface and inside the specimen with suppressing the decomposition of nickel hydride in polycrystalline pure nickel

ABSTRACT A finite element microstructure model with permeability tensors that considers crystallographic texture and grain size based on magnetic domain theory has been developed for the evaluation of magnetic anisotropy in polycrystalline steels. The model has proved capable of capturing the crystallographic texture, the grain size and the vector induction effects on the effective permeability behaviours

ABSTRACT The micromechanism-based stepwise strain hardening behaviour of copper single crystals significantly depends on the competition and collaboration between dislocation slip and deformation twinning. A crystal plasticity-based model of the strain hardening characteristics associated with slip and twinning interactions is proposed that focuses on modelling the stepwise strain hardening behaviour

ABSTRACT The precipitation of carbides at grain boundaries in nickel-based superalloys and austenitic stainless steels can significantly affect the grain boundary related properties of the bulk material. This study evaluated the growth and dissolution of carbides in grain boundary engineering (GBE) treated nickel-based superalloy (Inconel 690) during aging treatment using scanning electron microscopy

ABSTRACT Structural, electronic, magnetic, elastic and thermodynamic properties of Mn3GaN anti-perovskite have been studied using the first-principles calculations based on density functional theory (DFT) and Monte Carlo simulations within the Ising model. The structural investigation exposes the antiferromagnetic configuration stability of the compound. Also, the density of states (DOS) and band structure

ABSTRACT In this study, cracks propagating in WC grains are investigated at the atom scale along the [0001] axis. A brittle crack, characterised by cleavage along {1, 0, −1, 0} prismatic facets and the absence of dislocations is observed. The crack follows a zig-zag path allowing a higher deformation energy to be absorbed by the crystal. A ductile crack is also characterised. The plastic zone is limited

ABSTRACT The influences of Mn level (0–0.8 wt%) on the microstructure and mechanical properties of as-cast and T6 heat-treated low-silicon cast aluminium alloys were investigated. The results indicated that the addition of 0.5% Mn completely transformed the needle-like β-Fe phase in as-cast condition into a small-sized π-Fe phase, and the π-Fe phase was fully dissolved after T6 heat treatment. The

(2021). Alan Lidiard Obituary. Philosophical Magazine: Vol. 101, No. 8, pp. 905-906.

ABSTRACT An in-depth understanding of the role of non-metallic inclusions (NMIs) in the hydrogen-induced failure of structural materials is important in the manufacture and application of steels. In this paper we investigated the type, the amount and the distribution of NMIs in pipeline steels and their relation to the susceptibility to hydrogen-induced cracking (HIC). Scanning Electron Microscope

ABSTRACT A number of recent Molecular Dynamics (MD) simulations have demonstrated that screw dislocations in face centred cubic (fcc) metals can achieve stable steady state motion above the lowest shear wave speed ( vshear) which is parallel to their direction of motion (often referred to as transonic motion). This is in direct contrast to classical continuum analyses which predict a divergence in

ABSTRACT Natural pyrrhotites have gained significant attention due to their interesting electronic, antimicrobial, and chemical properties. The present work attempts to explore the morphology-induced modifications in the thermal characteristics of natural pyrrhotite due to ageing. The morphological, elemental, structure, optical, and thermal characterisations help in understanding the effect of ageing

ABSTRACT We employ molecular dynamics simulations to investigate the evolution dynamics of {101¯2} twinning in single-crystal Ti under shock loading. The shock compression applied perpendicular to the c-axis leads to the activation of {101¯2} twins in single-crystal Ti. We find the twin variant activation for each case of the applied loading conditions follows Schmid criterion. However, the time for

ABSTRACT Similarity has been proven between the Lifshitz topological transitions (LTT) in AB-stacked trigonally warped bilayer graphene (TWBG) and graphite near K points. The density of states (DOS) has been shown to have the van Hove singularities (VHS) of type (ϵc−|ϵ|)−1/2 at LTT in AB-stacked (TWBG) and graphite near K points. The topology evolutions of the iso-energetic lines at LTT have been established

ABSTRACT The spin-polarized full-potential linearized augmented plane wave (FP-LAPW) method based on the density functional theory (DFT) and the exchange and correlation potential is treated with the generalized gradient approximation (GGA) and the Coulomb repulsion (GGA + U), as well as the modified Becke-Johnson approach (GGA-mBJ) are investigated on the structural, elastic, electronic and magnetic

ABSTRACT Weakly interacting Fermi liquid can exhibit integer or fractional quantum Hall effect at sufficiently low temperatures, and in the presence of variable applied magnetic and/or electric fields. The said effects have been captured only incompletely by means of the Klitzing conductance formula, e2/h multiplied by the dimensionless filling factor (integer or fractional), ν because scattering rate

ABSTRACT Although the compressive strength of ice under both quasi-static [M. Arakawa and N. Maeno, Mechanical strength of polycrystalline ice under uniaxial compression. Cold Reg. Sci. Tech 26 (1997), pp. 215–229.] and dynamic [X. Wu and V. Prakash, Dynamic compressive behavior of ice at cryogenic temperatures. Cold Reg. Sci. Tech 118 (2015), pp. 1–13.] loadings shows an anomalous temperature effect

ABSTRACT In this paper, the influence of growth rates on the microstructure and magnetostrictive properties of Fe83Ga17 directional solidification alloys were investigated. The microstructure and magnetic properties of Fe83Ga17 as-cast and directional solidification samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), optical

ABSTRACT We employ molecular dynamics simulations to investigate the role of temperature on the evolution dynamics of the voids in single crystal iron. We simulate isotropic tension in single crystal iron at a constant strain rate with temperature in the range of 300–1200 K. We find that the number of voids is highest at 1200 K in comparison to that at 300 K indicating high nucleation events at high

ABSTRACT Non-uniform height semiconductor quantum rings are studied in order to determine their electronic and optical absorption properties. Theoretical modelling of the structure includes an analytical description of the non-regular multi-hilled confining potential as well as the presence of repulsive scattering centre and external crossing electric and magnetic fields. We have discussed the features

ABSTRACT In this report, SrFeO3-δ nanoparticle perovskite sample was prepared by the co-precipitation method. Rietveld refinement of the X-ray diffraction (XRD) data of SrFeO3-δ sample showed that it has a cubic phase (space group: Pm3 m). The morphology and average size (11.15 nm) of the SrFeO3-δ nanoparticle samples were characterised by the high-resolution transmission electron microscope (HRTEM)

ABSTRACT The temperature, hydrostatic pressure, and external electric field effects on the confined exciton in cylindrical quantum dots by considering a parabolic confining potential are investigated. The effects of these external perturbations on the binding energy and interband emission energy are calculated numerically by adopting the variational method within the effective mass approximation. Our

ABSTRACT A novel 3d transition metal high entropy alloy (3d TM HEA), Al0.5CoCuNiTi, was prepared by arc-melting. The phase component, microstructure, and mechanical properties in as-cast and annealed conditions were investigated. The results showed the phase structures of the studied alloys in both states were composed of FCC and BCC. The BCC phase was the absolute primary phase with a volume fraction

ABSTRACT We present Surface Evolver computer simulations for two-dimensional (2d) foams in which the contact angle at which liquid films and Plateau borders meet is non-zero. We determine the average coordination number Z of bubbles over a wide range of finite contact angles θ and liquid fractions ϕ. We find a linear scaling of Z for values of ϕ between about 0.07 and 0.15, corroborating previous data

ABSTRACT Good interface bonding is the basic prerequisite to achieve a high thermal conductivity of the composites. Clarifying the binding mechanism of Al/Mo2C interface is of great significance for the scheme design of Al/Diamond interface regulated by Mo element. The atomic structure and electronic properties of Al(111)/Mo2C(0001) interfaces and the influence of Mo doping on its adhesion work were

ABSTRACT In the literature, the volume of a cluster (i.e. a fluctuation of the solid solution or a precipitate) is identified as the volume of a sample of the bulk precipitate phase containing the same number of solute atoms (i.e. of the same size). This approximation is suitable for macroscopic precipitates but is debatable for a rigorous description of microscopic clusters, especially during the

ABSTRACT An understanding of nucleation, growth and coalescence of voids is required to predict the spall fracture. We employ molecular dynamics simulations to investigate the effect of temperature on the nucleation and growth of voids in single crystal copper under triaxial loading condition. We find that the void density decreases with an increase in temperature. The nucleation rate of the voids

ABSTRACT A number of recent Molecular Dynamics (MD) simulations have demonstrated that screw dislocations in face centred cubic (fcc) metals can achieve stable steady state motion above the lowest shear wave speed ( v s h e a r ) which is parallel to their direction of motion (often referred to as transonic motion). This is in direct contrast to classical continuum analyses which predict a divergence

ABSTRACT The occurrence of the anomalous behaviour of increased isothermal solidification completion time, tf with increasing temperature in transient liquid phase (TLP) bonding, is investigated for cases of one-dimensional and multi-dimensional migration of solid–liquid boundary, using a numerical model. The analysis shows that the anomalous behaviour is not restricted to the generally reported one-dimensional

ABSTRACT By adding alloying elements in Pt, the solid-solution strengthening is extensively used to improve the mechanical properties of Pt-based alloys, one of the most promising high-temperature materials due to its higher melting point. Yet the microscopic mechanism of the alloying effects on the mechanical properties of Pt is unclear. Based on a systematic study of the influence of alloying elements

ABSTRACT We investigate the magnetisation and internal energy of the David star in the Kagome lattice by the effective field theory developed by Kaneyoshi. First-order, Second-order and successive phase transitions are observed for different spin-down orientations. Spin-down orientation of identical atoms causes a second-order phase transition, spin-down orientation of different atoms causes a first-order

ABSTRACT The MnNiFeGe alloy is prepared by high-pressure annealing method. It is found that the martensitic transformation temperature after high-pressure annealing of this alloy decreases with the increasing thermal hysteresis. Besides, another magnetic phase transition above the martensitic transformation is observed, which is due to the existence of a large amount of retained austenite induced by

ABSTRACT Understanding the evolution of dislocations and twinning at the crack front is critical for designing micro-mechanical systems with improved performance. In this work, the dislocation evolution at the crack front in thin pre-cracked FCC single crystals is correlated with the associated fracture toughness, which is shown to be dependent on material specific properties such as stable stacking

ABSTRACT High-temperature oxidation behaviour of an alumina-forming austenitic (AFA, Febalance–20Ni–14Cr–2.5Al–0.15Si–2Mn–2.5Mo–0.9Nb, in wt%) steel and W-substituted AFA steel was examined. The isothermal oxidation tests were performed on the two steels at 780°C for 2 weeks in air, which indicated that the substitution of W for Mo was beneficial to improve the oxidation resistance of the AFA steel

ABSTRACT We investigate the effects of a time-dependent gate voltage on a spin–orbit interaction (SOI) coupled interacting double quantum dot (DQD) system. For a tunnel coupled detuned DQD with two interacting electrons, SOI couples triplet T 0 and hybridised singlet state (1,1)–(0,2) through spin nonconserving transition. In order to explore the effects of Ac gate voltage on charge localisation, we