The stress corrosion cracking(SCC) susceptibility of austenitic stainless steels 316Ti, HR3C, TP347 and nickel-based alloy 718 in supercritical water(SCW)at 550℃/25 MPa was studied. Slow strain rate tests (SSRT) were used to obtain tile stress-strain curves. The results show that the yield strength and tensile strength of 718 were much higher than those of the other three austenitic stainless steels while the elongation of 718 was significantly lower. Scanning electron microscopy observations of fracture surfaces reveal, that the failure mode of 316Ti and TP347 was transgranular ductile fracture, the failure mode of HR3C was both intergranular and transgranular ductile fracture and the failure mode of 718 was almost intergranular stress corrosion cracking (IGSCC).%研究了奥氏体不锈钢316Ti、HR3C、TP347和镍基合金718在550℃／25MPa超临界水中的应力腐蚀开裂（SCC）敏感性。通过慢应变速率拉伸试验得到相应的应力-应变曲线。结果表明，在本次试验工况下三种奥氏体不锈钢的屈服强度、抗拉强度和延伸率都非常接近，但镍基合金718的强度远高出其他材料，同时延伸率也大幅降低。扫描电镜对试样侧面以及断口形貌的观察分析发现：316Ti和TP347的失效模式均为穿晶韧性断裂；HR3C则表现为沿晶和穿晶的混合型韧性断裂；718的失效模式则几乎全是沿晶的脆性断裂。
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