摘要
为了研究多组元复合添加对钨基合金晶粒组织稳定性的影响,本工作制备了晶粒组织均匀、平均晶粒尺寸相近的W-10Cr和W-5Cr-5Sc超细晶合金,研究了2种钨基合金晶粒组织的热稳定性。结果表明,2种钨基合金晶粒突发长大的温度约为1300℃,比纯W提高了约200℃。在热失稳温度下晶粒长大指数和晶粒长大激活能均达到最小值,2种钨基合金的晶粒长大指数远大于纯W热失稳的晶粒长大指数,当温度超过热失稳温度后,W-5Cr-5Sc合金的晶粒长大速率比W-10Cr合金更小。W-10Cr合金的高温稳定化机制归因于富Cr相的析出和Cr的晶界偏聚,W-5Cr-5Sc合金的高温稳定化机制为富Sc相的析出以及Cr、Sc在晶界的共偏聚作用。
W-based alloys play an indispensable role in various fields,such as aerospace and nucle-ar industries.However,their thermal stability decreases with grain structure refinement,limiting their high-temperature applications.Although certain solute elements can enhance thermal stability through phase separation or grain boundary segregation,a systematic research on the extent of grain structure stabiliza-tion and the mechanisms of multicomponent addition is lacking.Herein,ultrafine-grained W-10Cr and W-5Cr-5Sc alloys with uniform grain structures and similar average grain sizes were prepared.The thermal stabilities of these W-based alloys were systematically investigated to elucidate their stabilization mecha-nisms.Results indicate that sudden grain growth occurs at approximately 1300 ℃ in W-10Cr and W-5Cr-5Sc alloys,representing an increase of approximately 200 ℃ compared with pure W.Kinetic analysis shows that the grain growth index and activation energy for grain growth are minimized at temperatures corresponding to thermal destabilization.Moreover,the grain growth indices of W-10Cr and W-5Cr-5Sc alloys exceed those of pure W during thermal instability.Furthermore,beyond the thermal destabilization threshold,the grain growth rate of the W-5Cr-5Sc alloy was lower than that of the W-10Cr alloy.The ad-dition of Sc modifies the Cr distribution in the alloy.In the W-10Cr alloy,the high-temperature stabilization mechanism of the grain structure was attributed to the precipitation of Cr-rich phases and the segregation of Cr at the grain boundaries.By contrast,the stabilization mechanism in the W-5Cr-5Sc alloy shifts to-ward the precipitation of Sc-rich phases along with the simultaneous segregation of Cr and Sc at the grain boundaries.
作者
杜文力
侯超
李昱嵘
韩铁龙
宋晓艳
DU Wenli;HOU Chao;LI Yurong;HAN Tielong;SONG Xiaoyan(Key Laboratory of Advanced Functional Materials,Ministry of Education,College of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China)
出处
《金属学报》
北大核心
2025年第11期1664-1672,共9页
Acta Metallurgica Sinica
基金
国家自然科学基金项目Nos.92163107和52371128。
关键词
钨基合金
热稳定性
晶粒长大动力学
晶界偏聚
W-based alloy
thermal stability
grain growth kinetics
grain boundary segregation
