Determining the elastic–plastic properties of materials with residual stress included using nanoindentation experiments and dimensionless functions

Residual stresses are widespread in materials and significantly affect their mechanical properties. In this paper, with the impact of residual stress taken into account, a method was proposed to reveal the elastic–plastic properties of materials, and the correctness of the method is verified using the example of laminar plasma quenched (LPQ) materials. Firstly, nanoindentation experiments were conducted on the LPQ materials. Then, the dimensionless functions corresponding to different residual stresses were characterized. Finally, the impact of residual stress on the dimensionless functions and nanoindentation response was discussed. The research results show that the hardened layer is made of isotropic material and that the hardened layer's yield stress and hardening index are obtained. There is a linear relationship between the residual stress and dimensionless functions.