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为设计更适用于先进单晶高温合金的均匀化-固溶热处理制度,研究了不同热处理温度和时间对一种先进单晶高温合金组织的影响。通过研究合金组织和元素分布发现,当温度直接升至γ′相溶解的实际起始温度1338℃时,合金不会发生初熔;当温度直接升至γ′相溶解的外推初始温度1350℃时,合金中出现了明显初熔,但初熔组织随着保温时间的延长逐渐减少;在1328℃固溶时,合金中虽然没有发生初熔,但均匀化效率明显降低。对实验结果进行了热力学和动力学计算与分析。结果表明,单晶高温合金的均匀化-固溶热处理窗口是一个动态的窗口,γ′相完全溶解温度和初熔温度均随着合金均匀化程度的提高而提高;高代单晶高温合金在均匀化-固溶热处理中,不须要将温度始终保持在铸态合金的初熔温度以下,只要保证温度低于合金所在均匀化状态对应的初熔温度即可;均匀化-固溶热处理中,提高每一台阶的温度可以得到的均匀化-固溶效果远优于延长热处理时间可达到的效果。根据实验及分析结果提出了一种适用于先进单晶高温合金的均匀化-固溶热处理制度设计方法,使合金在较短时间内得到了理想的合金组织和均匀化效果。
In order to design a homogenization-solution heat treatment system that is more suitable for advanced single crystal superalloys, the influence of different heat treatment temperature and time on the microstructure of an advanced single crystal superalloy was studied. By studying the microstructure and elemental distribution of the alloy, it is found that the initial melting will not occur when the temperature rises directly to 1338 ℃, where γ ’phase dissolves. When the temperature rises to 1350 ℃, , The initial primary melt appeared in the alloy, but the primary melt decreased gradually with the increase of the holding time. At the solution temperature of 1328 ℃, although the primary melt did not occur in the alloy, the homogenization efficiency was obviously decreased. The experimental results were calculated and analyzed thermodynamically and kinematically. The results show that the homogenization-solution heat treatment window of single crystal superalloy is a dynamic window. The γ ’phase complete melting temperature and initial melting temperature increase with the homogenization degree of the alloy. The single crystal superalloy Homogenization - solution heat treatment, do not need to keep the temperature below the initial melting temperature of the as-cast alloy, as long as the guaranteed temperature is lower than the initial melting temperature corresponding to the homogenized state of the alloy can be; homogenization - solution heat treatment, Homogenization can be achieved by increasing the temperature of each step - the effect of solution is much better than the effect of prolonging the heat treatment time. According to the experiment and the analysis results, a homogenization - solution heat treatment system design method suitable for the advanced single crystal superalloy was proposed, which made the alloy obtain the ideal alloy structure and homogenization effect in a short time.