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本文研究了Na_2SO_4,NaCl混合介质对一种镍基高温合金持久性能的影响。试验结果表明:75％Na_2SO_4+25％NaCl的混合介质使合金在750,800℃的持久寿命缩短,断裂塑性降低,持久曲线左移;90％Na_2SO_4+10％NaCl的混合介质对750℃的持久性能无明显影响;95％Na_2SO_4+5％NaCl的混合介质对800℃的持久性能也无明显影响;电解抛光增加合金对热盐腐蚀的敏感性。经金相、扫描电镜、电子探针等分析表明:热盐介质对持久性能影响是通过破坏试样表面保护性氧化膜使基体金属被氧化,且在应力作用下,氧化沿晶界向内部深入而造成。其影响程度与表面状态、盐的组分、应力大小有关。
In this paper, the effect of Na_2SO_4 and NaCl mixed media on the long-term performance of a Ni-based superalloy was studied. The results show that the mixing life of 75% Na_2SO_4 + 25% NaCl can shorten the service life of the alloy at 750 ℃ and 800 ℃, Obviously. The mixed medium with 95% Na_2SO_4 + 5% NaCl had no obvious effect on the persistence at 800 ℃. The electrolytic polishing increased the sensitivity of the alloy to hot salt corrosion. Metallographic analysis, scanning electron microscopy and electron probe analysis showed that the effect of the thermal salt medium on the permanent properties is that the base metal is oxidized by destroying the protective oxide film on the surface of the sample, and the oxidation proceeds deeply along the grain boundary under the stress And cause. The degree of influence is related to the surface state, the composition of salt, and the magnitude of stress.