ANALYSIS ON HARDNESS INDENTATION SIZE EFFECT BASE ON ENERGY BALANCE METHOD

To investigate the hardness indentation size effect (ISE) phenomenon,combining the nano-indentation technique and atomic force microscopy,load-depth curves and indentation images were obtained,and the plastic work in indentation process,max indentation depth,plastic deformation area and plastic deformation volume were calculated from these curves and images.Using these calculated data as variables,an improved hardness indentation size effect model is proposed based on the energy balance method,and the model can more sufficiently describe the hardness indentation size effect.The results for single crystal silicon inden- tation hardness test indicate that the consumption of energy to create a new surface is the main reason for the ISE phenomenon.With the increase in indentation depth,the consumption of energy to overcome the resistance force between the indenter and the specimen is the main reason for the decrease in indentation depth,and at smaller depths,the experimental equipment errors or the energy threshold at which an indenter creates a permanent indentation effect is more and more important and cannot be ignored.