High strain rate deformation mechanisms in fcc alloys as a function of load triaxiality

High strain-rate behavior and deformation mechanism of a multi-layer composite textured AZ31B Mg alloy plate

Texture effect on high strain rates tension and compression deformation behavior of extruded AM30 alloy

High strain rate deformation behavior of Al0.65CoCrFe2Ni dual-phase high entropy alloy

Microstructural evolution and dynamic mechanical behavior of PM 2195 Al-Li alloy with resistance to shear instability in high strain rate deformation

A new visco-plastic self-consistent formulation implicit in dislocation-based hardening within implicit finite elements: Application to high strain rate and impact deformation of tantalum

Impact of high strain rate deformation on the mechanical behavior, fracture mechanisms and anisotropic response of 2060 Al-Cu-Li alloy

Influence of phosphorus on hot deformation microstructure of a Ni-Fe-Cr based alloy

Role of [formula omitted] twinning in the anisotropy and asymmetry of AZ31 magnesium alloy under high strain rate deformation

A three-dimensional model for phase transformation of shape memory alloys (SMAs) during high strain rate deformation is developed and is then calibrated based on experimental results from an austenitic NiTi SMA. Stress, strain, and martensitic volume fraction distribution during high strain rate deformation are simulated using finite element analysis software ABAQUS/standard. For the first time, this paper presents a theoretical study of the microscopic band structure during high strain rate compressive deformation. The microscopic transformation band is generated by the phase front and leads to minor fluctuations in sample deformation. The strain rate effect on phase transformation is studied using the model. Both the starting stress for transformation and the slope of the stress–strain curve during phase transformation increase with increasing strain rate.

Investigation on the microstructure evolution and mechanical properties of electromagnetic rail material in a launch environment

Hot Compression Test of AA 2014 aluminum Alloy with Microstructure Analysis and Processing Maps

In order to investigate the effect of temperature on the anisotropic behaviour of AZ31 magnesium alloy rolling sheet under high strain rate deformation, the Split Hopkinson Pressure Bar was used to analyse the dynamic mechanical properties of AZ31 magnesium alloy rolling sheet in three directions, rolling direction(RD), transverse direction (TD) and normal direction (ND). The texture of the rolling sheet was characterised by X-ray analysis and the microstructure prior and after high strain rate deformation was observed by optical microscope (OM). The results demonstrated that AZ31magnesium alloy rolling sheet has strong initial {0 0 0 2} texture, which resulted at the obvious anisotropy in high strain rate deformation at 20 °C. The anisotropy reflected in stress–strain curve, yield stress, peak stress and microstructure. The anisotropy became much weaker when the deformation temperature increased up to 250 °C. Continuing to increase the deformation temperature to 350 °C the anisotropy of AZ31 rolling sheet essentially disappeared. The decreasing tendency of anisotropy with increasing temperature was due to the fact that when the deformation temperature increased, the critical resolved shear stress (CRSS) for pyramidal 〈c + a〉 slip, which was the predominant slip mechanism for ND, decreased close to that of twinning, which was the predominant deformation mechanism for RD and TD. The deformation mechanism at different directions and temperatures and the Schmid factor (SF) at different directions were discussed in the present paper.

In the present study, high strain rate deformation and flow characteristics of AA 6061 were investigated under dynamic uniaxial compression and combined compression and shear loading conditions. The uniaxial compressive behaviour was obtained at strain rates in the range of 102–104 s−1 using a split Hopkinson pressure bar (SHPB); ultrahigh strain rate plate impact compression and shear experiments were conducted to investigate the material behaviour at plastic strain rates in excess of 104 s−1. In order to understand the effect of material microstructure on the mechanical behaviour of the AA 6061 alloy, both the T6 and overaged (OA) heat treatments were investigated. The results of the SHPB experiments indicate that the two heat treatments show positive strain rate sensitivity at strain rates up to 4660 s−1. However, at strain rates in excess of 4660 s−1, Al6061-T6 exhibits a somewhat negative strain rate sensitivity. Estimates for temperature rise, assuming that all the plastic work is converted to heat, indicate that the specimen temperature may be elevated into a regime where both thermal effects on the flow stress and the resulting strain rate sensitivity change the flow stress response. This suggests that one contributing reason for the observed decrease in flow stress at the highest strain rates is due to thermal softening. Moreover, at strain rates in excess of 104 s−1, the flow stress levels for both the Al6061-T6 and Al6061-OA heat treatments are observed to approach their saturation stress levels.

Effect of high strain rate on plastic deformation of a low alloy steel subjected to ballistic impact

Metal matrix composites (MMCs) are candidate materials in the aerospace and automobile industries and have found increasing use in recent years. However, their low ductility resulting from the incorporation of reinforcement particles produces a lot of problems in forming process and limits their applications. A good solution to this problem in processing is to adopt superplastic forming (SPF). High strain rate superplasticity (HSRS) is attractive for industrial applications because SPF at high strain rates can reduce forming time greatly. High strain rate superplasticity and deformation mechanisms of powder metallurgy (PM) 6061 Al/SiCp (3 νm) composites have been investigated in this study. The extrusion ratios were 20 and 47. High temperature tensile tests were conducted over a temperature range of 853-871 K at initial strain rates of 0.001-1 s–1. Experiments show that PM 6061 Al/SiC (3 νm) composites exhibit good high strain rate superplasticity at temperatures of 853-871 K and high strain rates of 0·01-0·2 s–1. A maximum value of up to 450% was obtained at 871 K and 0·1 s–1 in the MMC3 specimen (6061 Al–10 vol.-%SiCp, extrusion ratio 47). The deformation mechanisms for HSRS were found to be dependent on the ratio of interfacial area to intergranular area β.