【摘要】 重型燃气轮机透平叶片长时服役过程中受温度和应力作用，将不可避免发生显微组织损伤。以国产定向凝固UGTC47合金为研究对象，研究其在850～950℃近服役温度范围内热暴露及热力耦合模拟1000、3000和5000 h后的显微组织演化。结果表明：经标准热处理的UGTC47合金在850～950℃热暴露及热力耦合模拟后，枝晶干γ′相的退化速度大于枝晶间区域的γ′相，枝晶干γ′相体积分数在退化初期就下降至60%左右；应力会促进γ′相体积分数趋于平衡状态，但在850、900和950℃热力耦合模拟5000 h下无显著差别，仍保持55%左右。γ′相尺寸基本符合LSW理论的生长模型。随着应力的增加和时间的延长，γ′相筏排化程度逐渐增大至0.6左右后趋于稳定，时间继续延长，甚至有所降低；γ相通道宽度随温度和应力增加呈线性增大趋势。更多还原

【Abstract】 During the long-term service of heavy-duty gas turbine blades, microstructural damage will inevitably occur due to temperature and stress effects. Microstructure evolution of domestically produced directionally solidified UGTC47 alloy after thermal exposure and thermal-stress coupling simulation at the near service temperature of 850-950 ℃ for 1000 h, 3000 h and 5000 h was studied. The results show that after thermal exposure and thermal-stress coupling simulation at 850-950 ℃, the degradation rate of γ′ phase in dendrite core of the standard heat treated UGTC47 alloy is greater than that of in interdendritic regions, and the volume fraction of γ′ phase in dendrite core decreases to about 60% in the early stage of degradation. Stress can promote the γ′ phase volume fraction towards an equilibrium state, but there is no significant difference after 5000 h of thermal-stress coupling simulation at 850 ℃, 900 ℃ and 950 ℃, still maintaining about 55%. The size of γ′ phase basically conforms to the growth model of LSW theory. As the stress and time increase, the rafting degree of γ′ phase gradually increases to about 0.6, then stabilizes, or even decreases with the time further increases. The channel width of γ phase shows a linear increasing trend with increasing temperature and stress.更多还原