Mathematical relationships linking flow stress to the deformation temperature have been developed describing the strain hardening behaviour of AISI 301LN metastable austenite steel at temperatures up to 75 °C. Sigmoidal flow stress relationships were dominant at most temperatures but reduced to Hollomon-type equations at a temperature of 90 °C and above. The observed sigmoidal behaviour was shown to

A sheet-shaped austenitic stainless steel (ASS) was processed by one ECASE pass. In this way, larger deformations were introduced close to the sheet edge vicinities, while the middle zone remained less affected by the deformation. The heterogeneous deformation produced larger amounts of deformation induced martensite (DIM) at the sheet edges, resulting in a heterogeneous structure along the sheet thickness

Carbon nanotube (CNT) yarns have demonstrated promising mechanical properties and scalability for composite applications. In this study, a commercially available continuous CNT yarn and two modified versions at large gauge lengths (~110 mm) were tested to reveal engineering properties. The as-received yarns with a large cross-section demonstrated the highest specific tensile strength (0.911 ± 0.137 N/tex)

FCC-type multicomponent alloys exhibit exceptional high strength during cryogenic deformation owing to thermally activated process. Inspired by this, we proposed that the γ-austenite of Fe-Mn-Cr-Si-Ni metastable multicomponent alloys would be strengthened by taking advantage of thermally activated process, and their shape memory effect would be improved by means of cryogenic deformation. As expected

The effect of nano-Y2O3 addition on microstructure and tensile properties of high-Al TiAl alloys prepared by induction skull melting is investigated. The result shows that the addition of nano-Y2O3 affords an obvious refinement in lamellar colony due to the heterogeneous nucleation. A crystallographic model is used to predict the α and γ nucleation potencies of Y2O3 particles during solidification

The conventional peak-ageing treatment of friction-stir welded AA2519 resulted in precipitation of a stable θ-phase instead of the expected strengthening dispersion of θ″ and θ′ thus degrading material strength. This phenomenon was attributed to acceleration of the precipitation kinetics due to grain refinement and over-ageing effect associated with the weld thermal cycle.

Nanostructured crystalline Al/amorphous AlN multilayer films, with a wide layer thickness (h) range from 10 to 200 nm, were prepared and exposed to high-temperature annealing from 200 to 600 °C. Microstructure of all the multilayers was highly stable under the temperature up to 400 °C. Apparent grain coarsening happened in multilayers with h > ∼50 nm under 500 °C. However, the Al grains in h ≤ ∼50 nm

We report new compositions of γ/γ′ Co base super alloys with low mass density where the strengthening γ′ precipitates are Co3(Al0.45V0.33Nb0.21) stabilised with a systematic replacement of Mo with V in Co–10Al–5Mo–2Nb (all in at.%) superalloy. The γ/γʹ microstructure is found to be metastable in nature that decomposes into equilibrium phases after 200 h of aging at 800 °C. Diffraction and atomic-scale

AlxCoCrFeNi is one of the most extensively studied high entropy alloy systems, as it has shown excellent mechanical properties suitable for structural applications. In this work, AlxCoCrFeNi(x = 0.3, 0.5, 0.7) alloys were successfully hot-forged without any visible cracks. Contributions from different strengthening mechanisms were estimated and compared with the experiment. Optical microscopy, x-ray

The stress corrosion cracking (SCC) susceptibility of an as-cast AZ80 magnesium alloy was evaluated using slow strain rate test (SSRT) in air and in 3.5% NaCl solution at various strain rates (10−5 s−1, 10−6 s−1, and 10−7 s−1). Furthermore, to elucidate the effect of aluminum content, the SCC susceptibility of an as-cast AZ31 alloy was also evaluated and compared with the as-cast AZ80 alloy. The SCC

Metal matrix composites have been developed to overcome the urgent demand of light-weight design. High entropy alloys (HEAs) are newly emerged as a new kind of potential reinforcement for metals due to their outstanding physical and mechanical properties. Here, a kind of novel Al matrix composite reinforced by Al0.8CoCrFeNi HEA particles was fabricated by multi-pass friction stir processing (FSP).

The synergetic effects of strontium (Sr) and rare earth elements (RE) on the modification of the microstructure and enhancement of the mechanical properties of as-cast Mg–9Al–1Zn alloy were studied. Based on the microstructural analysis, phase identification, and tensile tests, it was revealed that the combined RE and Sr addition results in superior mechanical properties compared to those of solo additions

Ti-30Zr-5Al-2.5Sn (TZAS, wt. %) is a novel α-type Ti-Zr based alloy. Herein, the effect of phase and microstructure evolution on mechanical properties of hot-rolled TZAS alloy with mixed α and α′ martensite phase were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy and statistical analysis. The content of primary α phase decreased as the hot-rolling

A ductile V0.5Nb0.5ZrTi refractory high-entropy alloy (RHEA) with relatively low density (~6 g/cm−3) is investigated, designed by controlling its valence electron concentration. The homogenized alloy exhibits a stable BCC structure, significant work hardening rate and considerable tensile stress (787 MPa) and elongation (21.9%). The solid-solution strengthening effect is estimated to be ~575 MPa by

The strain rate dependence of mechanical property in a selective laser melted (SLM) 17–4 precipitation hardening (PH) stainless steel with different states was investigated systematically by microstructure characterization, texture measurement and tensile test in the present study. The results reveal that as-built and annealed specimens have different initial microstructure and show the strain rate

In this study, novel Zn-Sn-xBi high-temperature solders were designed to join sintered NdFeB permanent magnets and steel. The effect of Bi addition on the corrosion resistance and mechanical properties of the soldered joints was systematically investigated. The results indicated that introducing Bi with specific content obviously decreased the undercooling of the solder. Reducing the undercooling by

The deformation behaviors of a hot-extruded Mg-2wt%Y alloy sheet with high activity for basal slip was studied under uniaxial tensile loading along the extrusion direction at room temperature. Using electron backscatter diffraction and crystal plasticity finite element method (CPFEM) simulation, this work proposed the direct evidence for the activation and the role of anomalous {101‾2} twinning: (1)

In this study, mechanical properties of hypereutectoid steels after thermomechanical processing have been evaluated using standard mechanical tests and a theoretical model has been developed using a novel artificial neural network approach. The K-folder cross validation (K-CV) was used to improve the generalized regression neural network (GRNN) to model and predict the lamellar spacing and mechanical

The origins of back stress strengthening were investigated in Fe-22Mn-0.6C and Fe-22Mn-0.6C-3Al TWIP steels. In contrast to reports found in literature, this study revealed that the high back stress developed in these steels is primarily caused by pile-ups of high density of geometrically necessary dislocations near the grain boundary regions rather than at deformation twins.

The feasibility of printing structures made of high-alloy TRIP steel by Electron Beam Melting (EBM) is demonstrated in this study. Three different structure geometries are discussed. During the melting process approximately 1.4 wt% manganese evaporate independent of the printed structure. The structures differ in the arrangement of cell walls and the local material distribution in the in-plane array

Continuous carbon fiber (CF) reinforced aluminum (Al) matrix composites have become a potential lightweight material in aerospace and commercial applications. In this work, the alumina (Al2O3) coating was uniformly synthesized on the surface of CF by the sol-gel method for improving the wettability and reducing the interfacial reaction between molten Al alloy and CF, while the Al2O3-coated CF was subsequently

The purpose of this study was to investigate post weld heat treatment (PWHT) of a heat resistant alloy steel used in gas turbines, in terms of microstructural evaluation, carbide phases formation and mechanical properties. EN10302.2002.X10CrMoVNb9-1(DIN1.4903) plates were welded by shielded metal arc welding process using an AWS E9015-B9 electrode, which is a cellulosic coated electrode. PWHTs were

High-strength ultrafine-grained Al–2Li (wt.%) alloy produced by accumulative roll bonding (ARB) process possessed poor uniform elongation, indicating that the ultrafine-grained Al–2Li alloy was susceptible to the inhomogeneous deformation (necking) and insufficient strain hardening. Through these strategies for designing and tailoring different microstructure: 1) suppressing recovery and recrystallization

In this paper, mechanical properties and microstructures of the cast and extruded Al-xCu-1Li-0.4Mg–1Zn-0.1Zr alloys (x = 2.0, 3.0, 4.0, 4.5, 5.5, 6.5 wt%) were investigated. The results showed that the as-cast micrographs of alloys with different Cu content primarily consist of dendritic α-Al grains, and the intermetallic phases at the grain boundaries were Cu and Zr rich phases. After solution treatment

This paper proposes a new in-situ hydrogen (H) charging bending technique to investigate the susceptibility to hydrogen embrittlement (HE) of high strength steels with limited ductility. The methodology is tested with generic martensitic Fe–C steels with a carbon (C) content of 0.2 wt%, 0.4 wt% and 1.1 wt%, respectively. The in-situ bending technique is developed to evaluate the hydrogen susceptibility

Selective laser melting (SLM) at different laser fluences was used to fabricate a TiC/Inconel 625 (TiC/IN625) nanocomposites. The influence of laser fluence on surface morphology, microstructure evolution, and mechanical properties of the TiC/IN625 nanocomposites were studied. The surface morphology of the TiC/IN625 nanocomposites was affected by the applied laser fluence, and the surface morphology

The deformation mechanism and precipitation behavior of Al-5.8Cu-0.35 Mg-(0.3Sn) (wt.%) alloys were intensively investigated by microstructure characterizations and mechanical tests in this work. The experimental results showed that the added Sn elements can induce profound impacts on the alloys in three manners: (1) the formation of Mg2Sn particles with excellent thermal stability can create particle-stimulated

In the automotive applications, sheet metals are inevitably subjected to pre-straining during stamping operation prior to spot welding. The integrity of vehicles is governed by the static and fatigue strengths of the joints. However, the effect of pre-strain on the tensile and fatigue properties of the spot-welds on the high strength low alloy (HSLA) steel sheets has not been well studied. To abridge

The hot working behaviour of additively manufactured Ti–6Al–4V pre-forms by Electron Beam Melting (EBM) has been studied at temperatures of 1000–1200 °C and strain rates of 0.001–1 s−1. As a reference, a wrought Ti–6Al–4V alloy was also analyzed as same as the EBM one. In order to investigate the hot working behaviour of these samples, all the data evaluations were carried out step by step, and the

The aim of this study was to characterize detailed interfacial microstructures and evaluate tensile properties of Al6061-to-Cu dissimilar welded joints via electromagnetic pulse welding (EMPW) at different discharge voltages. The EMPWed joints consisted of annular weld zone and central non-weld zone. The outer and inner regions of annular weld zone exhibited mainly diffusion bonding and mechanical

Aluminum composite material reinforced by single walled carbon nanotubes (SWCNT) was made by spark plasma sintering (SPS) followed by extrusion directly on spark plasma sintering machine. For the first time it was possible to carry out not only sintering by SPS method, but also extrusion of aluminum-based composites with SWCNT additives directly on the Labox 1575. The effect of the degree of cold deformation

To enhance the mechanical reliability without sacrificing the electrical conductivity of the flexible electronics, in this work submicron-thick Cu/Au/PI (CAP) and graphene/Cu/Au/PI (GCAP) films were fabricated successfully by using a series of assembly methods through introducing a graphene passivation layer onto the polyimide (PI)-supported Cu film surface, and a nanoscale gold (Au) interlayer between

In this study, roles of strain-hardening rate on susceptibility of adiabatic shear band (ASB) formation and subsequent cracking were investigated in two ultra-high-strength armor steel plates heat-treated differently. The quenched and tempered steel contained ~2% of retained austenite in the tempered martensitic matrix, while the quenched and austempered steel contained ~4% retained austenite in the

Cyclic torsion of micron-scale polycrystalline copper wires was experimentally studied. It was found that cyclic hardening is more pronounced with larger strain amplitude under symmetric cyclic straining. The mean stress relaxation is accelerated with larger initial strain and smaller strain amplitude under asymmetric cyclic straining. Meanwhile, both sample size and grain size effects were observed

In this work, the effect of holding durations (10–60min) during austempering at 300, 350 and 400 °C on the structure and properties of a 0.61C-1.71Si-0.86Mn steel has been studied. At all the austempering temperatures, austenite fraction gradually decreases with the increase in holding duration. Austempering temperature has been found to influence the rate of depletion of austenite. The effect of Mn

The effects of V and Nb addition on the microstructure and mechanical properties of a cold-rolled and intercriticallly annealed 5Mn steel were investigated. Compared to a steel without V or Nb the recrystallization in microalloyed steel was retarded significantly from the beginning of annealing, which resulted in a 100–200 MPa increase in both yield and tensile strength while the degradation of ductility

Slip/twinning activity and theoretical critical shear strengths (τmax) during room-temperature tensile deformation of as-extruded pure Mg and Mg-1wt.%Y sheets were investigated quantitatively via electron back-scattered diffraction (EBSD), scanning electron microscope (SEM) and first-principles calculation. Slip trace analysis results indicated the relative frequency of the active slip modes transformed

In this study, Al/Mg clad sheets were successfully obtained by multi-pass hot roll bonding. The effects of annealing on the evolution of interface microstructures and mechanical properties of the clad sheets were investigated. The interface microstructures were observed via scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The results

This work reports a novel effect of impurity element Cd on enhancing the precipitation kinetics and increasing the peak hardness of Al–Mg–Si(–Cu) alloys during artificial ageing. It is found that the number density of age hardening Mg–Si(–Cu) precipitates is greatly increased by Cd addition (~0.06 at.%) at both the under-aged and peak-aged stages. A systematic study on the precipitation behaviour by

The microscopic mechanism of high temperature (900 °C) fatigue crack growth in a single crystal Ni-based superalloy is investigated. Particular attention is focused to its relation to the cyclic misorientation markings (CMMs), formerly termed EBSD (electron backscattered diffraction) striation, left along the crack wake. Observation of a cross-sectioned crack tip is conducted by various electron microscopy

Through an innovative fatigue test design, the initiation and propagation of fatigue cracks were observed with a microscope in real time, and the effects of surface nanocrystallization on the fatigue properties of pure Zr were systematically studied in the work. The results showed that the fatigue limit of pure Zr treated by ultrasonic shot peening (USSP) for 45 min was up to 11.2% higher than that

The crack initiation mechanism and fatigue behaviour of thermomechanically processed PM Ti–6Al–4V was systematically studied as a function of microstructural modifications and the associated crystallographic texture. Uniaxial fatigue tests, fractographic analysis and thorough EBSD analysis were performed on an extruded blended elemental PM Ti–6Al–4V alloy to reveal the relationship between crystallographic

Transient liquid phase (TLP) technique has excellent potential for producing bimetallic devices in medical applications. TLP bonding between Co–Cr–Mo and Ti–6Al–4V metallic biomaterials was carried out using copper interlayer with a thickness of 10 μm at the bonding temperature of 900, 920, 940, and 960 °C. The effect of bonding temperature on the microstructural and mechanical characteristics was

The influence of 0.5 and 1.0 wt% Mn addition on the microstructure, texture, mechanical properties and biodegradability of the extruded Mg–4Zn alloy was investigated. The addition of Mn resulted in significant grain refinement as well as the formation of a strong fiber texture. The results of grain boundary misorientation analysis indicated that extension twinning plays an important role in dynamic

The effect of phosphorous on the hot-ductility of SA508Gr.4 N reactor pressure vessel (RPV) steel has been studied. The investigation is done with the use of a Gleeble machine in conjunction with optical metallography, scanning electron microscopy, and transmission electron microscopy. It is observed that both the undoped and P-doped steels exhibit hot-ductility troughs between 750 and 900 °C. However

Sufficient interfacial contact and adhesion are important factors for ensuring effective load transfer in carbon nanotubes (CNTs)-reinforced copper matrix composites (CMCs). In this study, a chemical unzipping method and matrix-alloying (addition of Cr) were integrated to solve these two challenges in CMCs. The results showed that partially-unzipped CNTs (PUCNTs) improved the restricted interfacial

The effect of the volume fraction of the long periodic stacking ordered (LPSO) phase on elevated temperature compressive deformation behavior is investigated using four types of Mg–Y–Zn alloys (Mg-0.4Y-0.2Zn, Mg–2Y–1Zn, Mg–5Y-2.5Zn, Mg–9Y–6Zn, where the numbers indicate at.%) produced by casting. The LPSO phase volume fraction is found to increase with increase in the concentrations of Y and Zn. The

A 13Cr austenitic stainless steel with a good combination of high yield strength, ductility and hydrogen embrittlement resistance was designed by combining hetero-deformation induced strengthening and martensitic transformation induced plasticity effects. Room temperature metastable austenite is promoted by adding 8 wt% Mn to a 13Cr–5Ni–2Mo supermartensitic stainless steel. A heterostructure consisting

Based on electron beam powder bed fusion, a novel process, called selective evaporation, is introduced, which could fabricate FGMs from a single material powder by irradiating different electron beam energy onto different locations in the powder bed to evaporate varying magnitude of aluminum element from a raw Ti47Al2Cr2Nb powder. A three dimensional FGMs of the (α + β) titanium alloy, with the aluminum

In this investigation, microstructural development and mechanical properties of an automotive grade AISI 4130 steel were explored through various heat treatment routes. In that regard, first of all the effect of austenitization temperature and time on the mechanical properties were assessed. Then, an optimum austenitization temperature was obtained for austempering at 400 °C and for the duration of

A series of high-entropy alloy CoCrFeNiV0.5Cx (x = 0.01, 0.02, 0.03 and 0.04) with low C content was fabricated. The alloys were hot rolled, homogenized, cold rolled and annealed for treatment processes. The structure and mechanical properties of the alloy were studied. The formation process of different interstitial carbides and their role in the alloy were discussed. In the original state, these

In view of the research of carbon nanotubes (CNTs) reinforced aluminum matrix composites (AMCs), weak CNTs/Al interface bonding and adverse interface reaction are the key scientific problems which restrict the strengthening effect of CNTs in AMCs. This study proposed a new idea of introducing SiC transition layer between CNTs/Al interface based on the composite configuration and interface structure

Instrumented indentation is a semi-destructive and robust technique to assess micromechanical characteristics (e.g., local properties) of metallic materials at ambient and elevated temperatures. In the present study, the instrumented indentation is employed to assess and compare the micromechanical response and fundamental mechanisms of plastic deformation (e.g., rate-controlling plasticity) in wire-arc

Impurities, particularly oxygen, are a critical issue to address in metal-injection-molding (MIM) processed Ti-Nb-Zr biomaterials. The addition of rare earth (RE) elements such as yttrium is a possible solution to the impurity problem due to their potential for scavenging oxygen. The impacts of added Y on the sinterability, microstructure and mechanical properties of the MIMed Ti-Nb-Zr, however, largely

Near-α Ti alloys are ideal candidates for high-temperature aerospace, automotive and nautical propulsion systems due to their high strength, low density and good corrosion resistance. However, the maximum service temperature of the well-known near-α alloy Ti6242S is limited to about 540 °C. By adding, for example, intermetallic γ-TiAl based alloy particles to Ti6242S powder a significant increase in