Deformation failure behavior and fracture model of twin-roll casting AZ31 alloy under multiaxial stress state
Weitao Jia, Lijuan Wang, Lifeng Ma, Huaying Li, Hongbo Xie, Yuan Yuan
Abstract
The influence of temperature and strain rate on the deformation behavior of twin-roll casting AZ31 alloy has been examined as a function of stress state using notched and un-notched tensile specimens. Failure behavior during the physical tension was carried out using FEM simulations with different fracture criteria. Using a combined experimental-FEM investigation, the applicability of each fracture criterion was verified to serve the prediction for the crack initiation under multiaxial stress state. Results show that the critical fracture strain presents a clear exponential relationship with stress triaxiality and strain rate, and a linear relationship with temperature. Through the quantitative analysis of the relationship, a mathematical model can be well established. After comparison and verification, the fracture model can accurately predict the forming limit during the plastic deformation of twin-roll casted AZ31 magnesium alloy under complex stress state, and the classical Cockcroft & Latham criterion is the most suitable criterion for predicting the related crack initiation.