Experiments and crystal plasticity simulations for the deformation behavior of nanoindentation: Application to the α₂ phase of TiAl alloy

In this work, nanoindentation experiments were carried out to investigate the deformation behavior of α₂ phase in Ti-43.5Al–4Nb–1Mo-0.1B alloy. The crystal plasticity simulations of nanoindentation process were implemented using the crystal orientation information obtained from the EBSD results. Through the combination of crystal plasticity finite element simulations and nanoindentation experiments, the constitutive parameters were calibrated and verified by comparing the hardness of simulated and experimental results. The mean error between simulation and experiment was 7.89%, which confirmed the accuracy of parameter calibration. Besides, the surface topography and the slip behavior were analyzed by the calculation of Schmid factors. Results revealed that the slip and pileup tend to occur at the areas with a large surface Schmid factor (SSF) and a small interior Schmid factor (ISF). In addition, the hardness and its connection with the slip behavior were discussed. It was found that the hardness of each grain is closely related to its crystal orientation. Among all the tested grains, the grain with Euler angle of (115.5°, 80.1°, 8.4°) has the lowest value of hardness, and the slip system (11‾00)[112‾0] plays a leading role in the deformation at the center of indentations.