Grain-orientation induced stress formation in AA2024 monocrystal and bicrystal using Crystal Plasticity Finite Element Method
Qi Zhao, Magd Abdel Wahab, Yong Ling, Zhiyi Liu
Abstract
Stress formation of monocrystals and bicrystals is investigated in specific oriented grains and grain boundaries of AA2024 alloy by using Crystal Plasticity Finite Element Method (CPFEM). The simulations show that the maximum Schmid factor (SF) value and the number of equivalent initial slip system (EISS) play a principal role in controlling the magnitude of internal stress within monocrystals. For bicrystal model, Goss and Cube grains are not the best ones for relieving stress concentration caused by their orientations, but they are the best ones for relieving grain boundary (GB) stress concentration. To this end, the dependence relations are discussed between GB stress and an advanced comprehensive factor combining SF, and geometry compatibility factor for 5 independent slip systems. It is found that this proposed comprehensive factor considering the contribution from 5 to independent slip systems effectively improves its dependence on GB stress.