A new simple and efficient method to determine critical strain required for adiabatic shear under high-speed impact
(1. College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China;
2. Research Institute of Hunan University in Chongqing, Hunan University, Chongqing 400044, China;
3. College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, China)
2. Research Institute of Hunan University in Chongqing, Hunan University, Chongqing 400044, China;
3. College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, China)
Abstract: Based on the investigation of mechanical response and microstructure evolution of a commercial 7003 aluminum alloy under high-speed impact, a new simple and effective method was proposed to determine the critical strain required for the nucleation of adiabatic shear band (ASB). The deformation results of cylindrical and hat-shaped samples show that the critical strain required for ASB nucleation corresponds to the strain at the first local minimum after peak stress on the first derivative curve of true stress-true strain. The method of determining the critical strain for the nucleation of ASB through the first derivative of the flow stress curve is named the first derivative method. The proposed first derivative method is not only applicable to the 7003 aluminum alloy, but also to other metal materials, such as commercial purity titanium, WY-100 steel, and AM80 magnesium alloy. This proves that it has strong universality.
Key words: critical strain; adiabatic shear band; high-speed impact; microstructure evolution; 7003 aluminum alloy