摘要
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。
An advanced single crystal superalloy was studied with different homogenization-solution heat treatments.The alloy microstructures and elements segregation were analyzed.The results show that no incipient melting appears when the alloy is directly heated up to 1338℃ ;when it is directly heated up to 1350℃,obvious incipient melting occurs at the beginning while gradually fades away with holding time;for 1328 oC,although there is no risk of incipient melting,the homogenization efficiency is far from satisfactory.It is concluded that for advanced single crystal superalloys,elevating temperatures of each step is much more effective than prolonging duration to get better heterogeneous effect;as the single crystal superalloy owns a dynamic homogenization-solution heat treatment window,there is no need to always keep the temperature below the incipient melting temperature of the as-cast condition,but keeping it below the incipient melting temperature of the alloy at the temporal homogenous state is necessary.Based on above conclusions,a new approach is introduced to design effective homogenization-solution heat treatments for advanced single crystal superalloys,and it has been successfully used on the alloy in this study.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2017年第6期1530-1535,共6页
Rare Metal Materials and Engineering
关键词
单晶高温合金
均匀化
固溶
热处理
设计
single crystal superalloy
homogenization
solution
heat treatment
designing
