Stress corrosion cracking (SCC) susceptibility of a new nickel‐based alloy C‐HRA‐2 under two types of superheated steam (SHS) (0.1 and 8 MPa) and supercritical water (SCW) (25 MPa) at 650°C was studied through slow strain rate tensile tests at a strain rate of 5 × 10−7 s−1. The results indicate that C‐HRA‐2 exhibits SCC susceptibility in both SHS and SCW, and the susceptibility increases with increasing pressure. Transgranular fracture (located inside) characterized by dimples/micropores and intergranular fracture (located at the edge) characterized by rock‐sugar‐like morphology was observed in all specimens. The brittleness of the alloy increases with the increase of medium pressure. A large number of cracks perpendicular to the loading axis were noticed on the gauge surface. The SCC mechanism of C‐HRA‐2 under steam and SCW is dynamic embrittlement.

中文翻译：

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新型镍基合金在不同环境下的应力腐蚀开裂敏感性

研究了新型镍基合金 C-HRA-2 在 650°C 两种过热蒸汽 (SHS)（0.1 和 8 MPa）和超临界水（SCW）（25 MPa）下的应力腐蚀开裂（SCC）敏感性通过应变率为 5 × 10 的慢应变率拉伸试验−7s−1。结果表明，C-HRA-2 在 SHS 和 SCW 中均表现出 SCC 敏感性，并且敏感性随着压力的增加而增加。在所有样品中都观察到以韧窝/微孔为特征的沿晶断裂（位于内部）和以类岩糖形态为特征的沿晶断裂（位于边缘）。合金的脆性随介质压力的增加而增加。在量规表面上观察到大量垂直于载荷轴的裂纹。 C-HRA-2在蒸汽和SCW下的SCC机制是动态脆化。