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研究了纯 Na_2SO_4,10%NaCl+90%Na_2SO_4和20%NaCl+80%Na_2SO_4三种盐沉积对 GH37镍基合金在750—850℃范围内蠕变性能的影响.结果表明前两种盐对蠕变性能无明显影响,而20%NaCl+80%Na_2SO_4混合盐当沉积量达到3mg/cm~2时严重地缩短蠕变断裂时间,并降低蠕变断裂延伸率.沉积在合金表面的20%NaCl+80%Na_2SO_4混合盐破坏了氧化膜 Cr_2O_3的保护作用,在合金表层同时发生均匀腐蚀和沿晶腐蚀,在基体一侧产生贫 Cr 带,同时氧和硫沿晶界侵入,外力作用下发生沿晶开裂.表层沿晶裂纹和体内蠕变产生的沿晶裂纹相互联结大大地缩短了蠕变第二阶段的时间,导致过早断裂.
The effect of three salt depositions of pure Na_2SO_4, 10% NaCl + 90% Na_2SO_4 and 20% NaCl + 80% Na_2SO_4 on the creep properties of GH37 nickel-base alloy in the range of 750-850 ℃ was studied. However, 20% NaCl + 80% Na_2SO_4 mixed salt seriously shortens the creep rupture time and decreases the elongation at creep rupture when the deposition amount reaches 3mg / cm ~ 2. + 80% Na_2SO_4 mixed salt destroys the protective effect of the oxide film Cr_2O_3. At the same time, uniform corrosion and intergranular corrosion occur on the surface of the alloy, resulting in a Cr-depleted zone on the substrate side. Oxygen and sulfur intrude along the grain boundaries and occur along the grain boundaries Crystal Cracking The interdependency of intergranular cracks created by the intergranular cracks and in-body creep greatly shortened the second phase of creep, leading to premature fracture.