采用慢应变速率拉伸(SSRT)试验研究了奥氏体不锈钢316Ti在550 ℃/25 MPa、600 ℃/25 MPa和650 ℃/25 MPa超临界水(SCW)中的应力腐蚀开裂(SCC)敏感性, 及其在超临界650 ℃/25 MPa、次临界290 ℃/15.2 MPa水环境中的均匀腐蚀性能;同时研究了其在空气中不同温度条件下的机械强度。结果表明, 随着温度的升高, 316Ti的机械强度和延伸率逐渐下降; 试验后断面SEM表明, 316Ti在550 ℃和600 ℃时具有应力腐蚀开裂的倾向, 在650 ℃时没有应力腐蚀开裂倾向, 但在三种温度下试样标距段均未发现裂纹。参照其在空气中不同温度下的机械强度数据, 可知其屈服强度和抗拉强度基本上随温度的升高而降低。316Ti在超临界水环境中的腐蚀试验表明, 其腐蚀呈现出增重特征, 并且满足幂函数生长规律; 而其在次临界条件下的腐蚀却呈现出减重的特征。

The susceptibility to stress corrosion cracking (SCC) of 316Ti in supercritical water (SCW) at 550 ℃/25 MPa, 600 ℃/25 MPa and 650 ℃/25 MPa respectively, and the general corrosion behavior in supercritical water at 650 ℃/25 MPa and in subcritical water at 290 ℃/15.2 MPa respectively were studied. The mechanical properties of 316Ti were also investigated at different temperatures in air. The strain-stress curves obtained from slow strain rate tensile (SSRT) tests showed that the strength and elongation of 316Ti decreased as the temperature increased. The ex-situ scanning electron microscopy (SEM) showed that 316Ti had susceptibility to SCC only at 550 ℃ and 600 ℃. The tests in air showed that the yield strength and tensile strength of alloy 316Ti decreased as the temperature rose. The general corrosion experiment in supercritical water showed that the weight gain was subject to power function growth kinetics, while the one in subcritical water indicated the weight loss.