Abstract:

powerful method for the characterization of microstructures of crystalline materials in terms of crystallite size and

dislocation structures. In this paper the effect of the sliding on the microstructure of A356 in the as-cast and heat

treated conditions are studied, The X-ray phase analysis shows that with increasing applied load, the dislocation

density is increased, whereas the crystallite size is decreased. It was found that heat treatment raised dislocation

density during wear. The screw or edge character of dislocations in worn specimens were determined by analyzing the

dislocation contrast factors, it was demonstrated that the character of the prevailing dislocations in high loads is

nearly pure screw.