Effect of shot peening on surface mechanical properties of TiB2/Al composite

The influence of shot peening on the surface mechanical properties of the TiB2/6351Al composite has been investigated. The microstructures were determined by X-ray diffraction line profile analysis. The results showed that the increment of hardness was about 50% in the top surface layer. The matrix proof stress σ0.2 of the shot peened surface had been increased by 27% and the whole strength increment was about 21% by considering the contribution of the reinforcements. The domain size and the dislocation density in the strengthened surface were 55 nm and 3.67 × 1015 m−2, respectively. The mechanical properties improvement of the modified surface was partially due to the reinforcements but mainly due to the fine domains, high value of dislocation density induced by shot peening.