The invention relates to a method for identifying the
mechanical property of each composition phase of a multiphase material, which comprises the following steps: firstly, pretreating the surface of a material to be detected, obtaining
grain orientation and
grain boundary distribution through EBSD, selecting an indentation position in a target phase single grain, and implementing a
nanoindentation experiment to obtain a load-displacement curve; then, scanning the three-dimensional morphology of the indentation through AFM, and extracting the depth of a feature point; establishing a
single crystal three-dimensional
nanoindentation CPFEM model, endowing
crystal orientation measured by EBSD, and simulating to obtain a curve and morphology depth; fitting an experiment curve and a
simulation curve by using a
parabolic function to obtain a characteristic coefficient, and incorporating the characteristic coefficient and the morphology depth into a
back analysis objective function; and finally, carrying out
back analysis by adopting a
global optimization algorithm to solve
crystal plasticity parameters, and outputting a
single crystal constitutive parameter set. Compared with the prior art, through curve and morphology double-information constraint and three-
dimensional simulation, the deviation of a traditional method is overcome, the parameter identification precision and reliability are improved, and the method is suitable for multi-phase materials such as high-strength steel and
titanium alloy.