Abstract: The regularity and mechanism of the microplastic deformation of steel 1Cr18Ni9Ti both solu- tion-treated and prestrained were investigated.In the different stages of microplastic deformation,stage 1 corresponds to the dislocation moving and exhausting in the regions near grain boundaries.Stage 2,being the early stage of macroplastic deformation,corresponds to the extensive operation and generation of dislocations in the interior of grains and also dislo- cation emission from the grain boundaries.The regularities of the effect of prestrain on macro-and micro-yield strength are different.

Key words: microplasticity, 1Cr18Ni9Ti, dislcoation