Study on Dynamic Mechanical Behavior of Al-Mg-Si Alloy

Abstract

The dynamic mechanical behavior of Al-Mg-Si alloy was investigated under different strain rates by mechanical property and microstructure characterization, constitutive behavior analysis and numerical simulation in the present study. As the strain rate increases, the yield strength, ultimate tensile strength and elongation increase first, then remain almost constant, and finally increase. The alloy always exhibits a typical ductile fracture mode, not depending on the strain rate. However, as the strain rate increases, the number of dimples gradually increases. Tensile deformation can refine grains, however, the grain structure is slightly affected by the strain rate. An optimized Johnson-Cook constitutive equation was used to describe the mechanical behavior and obtained by fitting the true stress-strain curves. The parameter C was described by a function related to the strain rate. The fitting true stress-strain curves by the JC model agree very well with the experimental true stress-strain curves. The true stress-strain curves calculated by the finite element numerical simulation agree well with the experimental true stress-strain curves.

Keywords

Al-Mg-Si alloy / strain rate / mechanical property / microstructure / Johnson-Cook model / finite element simulation

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