Evolution process of adiabatic shear localization in TC18 titanium alloy and 30CrMnSiNiMoV steel

Adiabatic shear localization has been studied by many researchers, both from mechanical and material viewpoints. However, the studies on microstructure characterization of nucleation and development of ASB combining with mechanical response have shown less prosperous compared with either separate study. In this paper, a novel approach is put forward to carry out precisely controlled dynamic compression tests on TC18 titanium alloy and 30CrMnSiNiMoV steel. Stopper rings with a series of height range were used to precisely control the deformation amount of materials. The experimental results showed that, nucleation and development of adiabatic shear localization of two materials can be "frozen" with the precisely controlled compression tests. Restricted with the different height stopper rings, the stages of non shear localization deformation, short and long shear bands, as well as cracks can be captured. Under certain strain rate or compression pressure, critical strain and nucleation time of ASB initiation can be determined from both the stress-strain curve and microstructure observation results. Nucleation point of ASB in titanium alloy and steel usually occur earlier than the collapse point of stress-strain curves. The materials can stand additional dynamic loading after occurrence of ASB.