GH742高温合金激光冲击强化和喷丸强化残余应力

Residual Stresses of GH742 Superalloy Induced by Laser Peening and Shot Peening

对GH742高温合金进行激光冲击强化和喷丸强化,利用X射线应力分析仪测定强化层的残余应力,对比分析2种残余应力的差异和特征,并采用不同的退火温度进行退火,研究表面残余应力在高温下的稳定性。结果表明,2种表面强化方法都可以在GH742高温合金表层引入残余压应力,但激光冲击强化试样比喷丸强化试样具有更深的残余压应力层和较好的稳定性,且残余压应力最大值在表面;与激光冲击强化的试样相比,喷丸强化试样的残余压应力较浅,而且随着喷丸强度的增加,最大残余压应力也由表面移向了次表面。

Laser peening and shot peening were performed for GH742 superalloy. Then the residual stress of the peened surfaces was determined by an X-ray diffraction stress analysis tester. The characteristics of compressive residual stresses induced by the two kinds of surface enhancement processes were compared. The alloy was annealed at different temperatures and the stability of surface residual stress at high temperatures was investigated. Results show that both laser peening and shot peening can induce compressive residual stresses into the surface layer. However, the laser peened alloy, whose maximal compressive residual stress locates at the surface, exhibits deeper compressive residual stress layer and better stability than the shot peened alloy. For the shot peened alloy, the compressive residual stress is shallow, and its maximum stress moves from the surface to the subsurface with the increase of shot peening intensity.