In this study, a nickel-based powder metallurgy alloy was processed via turning, ceramic bead peening, and shot peening by high-intensity cast-iron shots and low-intensity ceramic beads (denoted as compound shot peening). We investigated the surface morphology (surface stress concentration factor, K_st), the surface residual stress profile, microstructure, and the hardness gradient of three surface states and compared the high-temperature low-cycle fatigue lives. The results showed that the surface stress concentration coefficients after turning, ceramic bead peening, and compound shot peening were 2.39, 1.98, and 2.12, respectively. The average surface roughness, S_a, after turning was low, but the bottom of the tool mark was sharp, so the K_st value was higher than that after shot peening, which formed a round bottom by bead blasting. Compared with ceramic bead peening, a surface structure with a deeper compressive residual stress profile and a higher hardness gradient was formed after compound shot peening, and nanostructured features appeared on the outermost surface. The estimated low-cycle fatigue lives after the ceramic bead peening and compound shot peening were 0.99 and 3.13 times longer than after the turning process respectively with strain amplitude 0.5% at 538℃. Moreover the gain of compound shot peening on low cycle fatigue performance gradually decreases with the increase of the strain amplitude.

在这项研究中，镍基粉末冶金合金通过车削、陶瓷珠丸强化和高强度铸铁丸和低强度陶瓷珠丸（称为复合喷丸）进行喷丸处理。我们研究了三种表面状态的表面形貌（表面应力集中因子，K _st）、表面残余应力分布、微观结构和硬度梯度，并比较了高温低周疲劳寿命。结果表明，车削、​​陶瓷珠粒喷丸和复合喷丸后的表面应力集中系数分别为2.39、1.98和2.12。车削后的平均表面粗糙度 S _a低，但刀痕底部锋利，因此 K _st值高于喷丸后，喷丸形成圆底。与陶瓷珠粒强化相比，复合喷丸后形成的表面结构具有更深的压缩残余应力分布和更高的硬度梯度，并且在最外层表面出现纳米结构特征。在 538℃应变幅值 0.5% 时，陶瓷珠粒喷丸和复合喷丸后的估计低周疲劳寿命分别是车削后的 0.99 倍和 3.13 倍。此外，复合喷丸对低周疲劳性能的增益随着应变幅值的增加而逐渐减小。