最新色国产精品精品视频,中文字幕日韩一区二区不卡,亚洲有码转帖,夜夜躁日日躁狠狠久久av,中国凸偷窥xxxx自由视频

Effects of laser peening and shot peening on fatigue performance of the powder metallurgy nickel-based FGH97 superalloy were investigated. Compressive residual stresses in the surface layer were analyzed by the X-ray diffraction stress analyse tester. The rotating bending fatigue test at 650℃ was used to compare the surface enhancement effects between laser peening and shot peening. Moveover, the fatigue fracture characteristics were analyzed by scanning electron microscope. The results showed that both laser peening and shot peening can improve the fatigue property of FGH97, but laser peening had much better surface enhance effect than shot peening due to deeper compressive residual stress layer and good surface roughness, and the compressive residual stresses induced by laser peening were more stable than ones by shot peening under fatigue process at high temperature. Furthermore, the fatigue crack sources of both laser peened and shot peened speciemens initiated subsurface, while untreated at the surface.