Study on Dynamic Mechanical Properties and Deformation Mechanism of TWIP Steel

Abstract:

The quasi-static and dynamic mechanical properties of TWIP steel were investigated by using Zwick/Roell Z100 universal testing machine and Hopkinson tensile bar. The strain hardening and strain strengthening in Johnson-Cook dynamic constitutive model were modified based on mechanical test results. The microstructure of TWIP steel before and after tensile deformation were analyzed by XRD, SEM and EBSD. The findings demonstrate that: When subjected to quasi-static loads, TWIP steel exhibits negative strain rate sensitivity and positive strain rate sensitivity when subjected to dynamic loads. Twinning induced plasticity is the primary deformation mechanism of TWIP steel during tensile process, and slip also plays a significant role. The initial strain and volume fraction of deformation twins in TWIP steel under dynamic loading are smaller than those under quasi-static loading. TWIP steel has exceptional strength and plasticity because deformation twins and the grain refinement brought on by twin contact, implying that it has a broad application in the fields of impact resistance and anti-explosion.

Key words:TWIP steel; Dynamic mechanical properties; Deformation mechanism; Deformation twin; Dynamic constitutive model