不同强度喷丸处理后铝锂合金表面的残余应力

Surface Residual Stress in Aluminum-Lithium Alloy Shot-Peened at Different Shot Peening Intensities

在不同喷丸强度下对铝锂合金进行了表面喷丸处理,采用X射线衍射法和盲孔法分析了其表面及近表层的残余应力。结果表明:采用不同喷丸强度处理后试样表面90°方向(平行喷嘴移动方向)的残余压应力高于0°方向(垂直喷嘴移动方向)的,90°方向的衍射峰积分宽度大于0°方向的,说明喷丸强化后试样在90°方向产生了更大的微应变;试样近表层残余压应力随层深的增加先增大后减小,最终趋于0;较高强度喷丸处理后试样表面和距表面0.15mm内的残余压应力小于较低喷丸强度处理的,而最大残余压应力、最大残余压应力深度以及残余压应力场深度均大于较低强度喷丸处理后的。

The aluminum-lithium alloy was surface hardened at different shot peening intensities, and then the residual stresses in the surface and near-surface layers were analyzed by X-ray diffraction and the hole-drilling strain-gage method respectively. The results show that the surface residual stresses in 90° direction （parallel to moving direction of the nozzle） of the specimens treated at different shot peening intensities were higher than those in 0° direction （perpendicular to moving direction of the nozzle）, and the integral breadth of the diffraction peak in 90° direction was larger than that in 0° direction, indicating that more micro-strains were generated in 90° direction of the specimen after shot peening. With the increase of the depth, the residual compressive stress in the nearsurface layer of the specimen first increased then decreased, and finally approached zero. The residual stresses induced after treated at a relatively strong shot peening intensity at the surface and within 0.15 mm below the surface of the specimen were lower than those induced at a relatively weak intensity, while the maximum residual compressive stresses and the depth of the maximum residual compressive stress and the residual compressive stress field were larger than those at a relatively weak intensity.