The modified temperature term on Johnson Cook model for AZ31 magnesium alloy

Materials Science and Technology

Mao

et al. 2022

In this research, the dynamic compression behaviour of 5 and 1.5 µm grain size samples of Mg–4Zn–1Y alloy was investigated by the split Hopkinson pressure bar at the strain rate of 1000–1700 s−1. The microstructure, texture evolution, and the deformation mechanisms of samples were characterised by electron backscattering diffraction. The result showed that the grain refinement caused tension twining, which resulted in the distinct true stress–strain curves with specific grain sizes. It was found that the pyramidal < c + a > and pyramidal <a > slips were the main deformation mechanisms of 5 and 1.5 µm samples under dynamic compression, respectively. The constitutive modelling of Mg–4Zn–1Y with different grain sizes was also developed by introducing the grain size adjustment parameters.

“…To ensure the accuracy of the experiment and test data obtained, the compression testing was repeated three times. The detailed experimental procedure can be found elsewhere [24].…”

Section: Experiments and Methodsmentioning

confidence: 99%

Dynamic compression behaviour and constitutive description of fine-grain Mg–4Zn–1Y alloy

Materials Science and Technology

Mao

et al. 2022

“…Mao et al [12] studied the dynamic compressive mechanical properties and failure behaviour of extruded Mg–8Gd–5Y magnesium alloy with an average grain size of about 10 µm, which belongs to the same category of alloy system as Mg–7Gd–5Y–1.2Nd–0.5Zr. The results of high strain rate compression showed that the extruded magnesium Mg–8Gd–5Y alloy specimens yielded continuously along ED, TD, and ND directions, and exhibited a positive strain rate effect; however, their anisotropy was not as obvious as that of commercial magnesium alloy AZ31 [13].…”

Section: Introductionmentioning

confidence: 99%

Deformation behaviour of ultrafine grained Mg–7Gd–5Y–1.2Nd–0.5Zr alloy under high strain rates

Tang

Materials Science and Technology

et al. 2019

The mechanical behaviour of Mg–7Gd–5Y–1.2Nd–0.5Zr (wt. %) alloy with ultrafine grains was measured by split Hopkinson pressure bar method under the strain rates of 1000, 1500, and 2000 s−1 at room temperature. Dynamic tests were carried out along extrusion direction (ED), transverse direction (TD), and normal direction (ND). The results demonstrated that the flow stress increased with the increase of strain rate, showing a positive strain rate strengthening effect. There was no obvious anisotropy in dynamic compression along ED, TD, and ND, which was caused by rare earth elements and multi-pass deformation. This led to the adoption of plastic deformation mode dominated by non-basal slip and participated by tension twinning.

Localized deform behavior of AZ31B magnesium alloy by numerical simulation

Zhang

Materialwissenschaft Werkst

Mao

et al. 2019

Self Cite

The dynamic compression behavior of AZ31B magnesium alloy with hat shaped specimen was investigated at high strain rate in this paper. Based on the Johnson‐cook constitutive model and fracture model, the interaction of temperature, stress and strain fields of AZ31B magnesium alloy with hat shaped specimen were numerically simulated by using ANSYS/LS‐DYNA software under different strain rates, which was validated by experiment. It is found that the plastic strain is highly concentrated on the corner of the hat shaped specimen, which leads to large localized deformation. The voids are nucleated and extended by compression stress. Work harden effect is caused by remained plastic strain, which is located around adiabatic shear band. The stress collapse is discovered in gauge section, which is also discovered in experiment. Thermal soften effect is suppressed with the strain rate increased.