Evaluation of Dislocation Structure and Crystallite Size in Worn Al-Si Alloy by X-Ray Diffraction

Diffraction peak profile analysis has recently been developed to such an extent that it can be applied as a 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 weal: The screw or edge character ofdislocations 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.