We investigated the effect of ultrasonic shot peening on the surface integrity and fatigue properties of single-crystal superalloys. The results show that ultrasonic shot peening significantly reduces the surface roughness of single-crystal specimens and improves surface finishing. The surface hardness increases by 49 %, reaching more than HV660. At the same time, the microstructural analysis illustrates that the single-crystal surface layer after ultrasonic shot peening forms a nanoscale refined sub-crystalline structure that rotates along the [110] axis. It significantly improves the mechanical properties of the surface metal. The originally existing round casting micro-pores are elongated along the [001] axis, forming a willow shape - elliptical shapes from the surface inward, reducing the stress concentration of the casting micro-pores perpendicular to the [001] axis. Combining the above three modification effects, the fatigue limit of the single-crystal notched Kt = 3 sample at 650 ℃ strengthened by ultrasonic shot peening is 94.2 % higher than that of the as-received notched sample, and 17.4 % higher than that of the smooth sample.

我们研究了超声波喷丸处理对单晶高温合金表面完整性和疲劳性能的影响。结果表明，超声喷丸处理可显着降低单晶试样的表面粗糙度并改善表面光洁度。表面硬度提高了49％，达到了HV660以上。同时，微结构分析表明，超声喷丸处理后的单晶表面层形成了沿[110]轴旋转的纳米级细化亚晶结构。它显着改善了表面金属的机械性能。最初存在的圆形铸造微孔沿[001]轴拉长，形成柳树形-从表面向内的椭圆形，降低垂直于[001]轴的铸件微孔的应力集中。结合上述三种改性效果，经超声喷丸强化的650℃单晶缺口Kt = 3样品的疲劳极限比所接受的缺口样品高94.2％，比缺口试样高17.4％。光滑的样品。