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热处理对定向凝固Nb-Ti-Si基超高温合金组织和显微硬度的影响
引用本文:郭海生,郭喜平.热处理对定向凝固Nb-Ti-Si基超高温合金组织和显微硬度的影响[J].中国有色金属学会会刊,2011(6):1283-1290.
作者姓名:郭海生  郭喜平
作者单位:西北工业大学凝固技术国家重点实验室;
基金项目:Project(51071124)supported by the National Natural Science Foundation of China; Project(CX200605)supported by the Doctorate Foundation of Northwestern Polytechnical University,China; Project(20096102110012)supported by a Special Research Fund for Doctoral Disciplines in Colleges and Universities of the Ministry of Education,China
摘    要:对定向凝固Nb-Ti-Si基超高温合金分别进行(1500℃,50h)的均匀化处理以及(1500℃,50h+1100℃,50h)的均匀化+时效热处理。结果表明:热处理后合金组织更加均匀,大尺寸初生(Nb,X)5Si3(X代表Ti和Hf元素)块逐渐溶解或破碎,并且定向凝固共晶团中的大部分片状铌基固溶体Nbss以及(Nb,X)5Si3变得短、粗;热处理能够有效消除定向凝固态合金中不同区域Nbss内存在的元素偏析,各元素偏析比在热处理后均趋向于1;热处理后,组织的显微硬度增加,最大值达到了HV1404.57,较定向凝固态合金中共晶组织的显微硬度增加了72.8%。

关 键 词:Nb-Ti-Si基超高温合金  均匀化处理  时效处理  组织变化  显微硬度

Microstructure and microhardness of directionally solidified and heat-treated Nb-Ti-Si based ultrahigh temperature alloy
GUO Hai-sheng,GUO Xi-ping State Key Laboratory of Solidification Processing,North western Polytechnical University,Xi'an ,China.Microstructure and microhardness of directionally solidified and heat-treated Nb-Ti-Si based ultrahigh temperature alloy[J].Transactions of Nonferrous Metals Society of China,2011(6):1283-1290.
Authors:GUO Hai-sheng  GUO Xi-ping State Key Laboratory of Solidification Processing  North western Polytechnical University  Xi'an  China
Affiliation:GUO Hai-sheng,GUO Xi-ping State Key Laboratory of Solidification Processing,North western Polytechnical University,Xi'an 710072,China
Abstract:Directionally solidified (DS) specimens of Nb-Ti-Si based ultrahigh temperature alloy were heat-treated at (1 500 ℃, 50 h) and (1 500 ℃, 50 h) + (1 100 ℃, 50 h), respectively. The results show that the microstructures become uniform, the long and big primary (Nb,X)sSi3 (X represents Ti and Hf elements) plates in the DS specimens are broken into small ones, and the eutectic cells lose their lamellar morphology and their interfaces become blurry after heat-treatment. Meanwhile, the (Nb,X)sSi3 slices in the eutectic cells of the DS specimens coarsen obviously after heat-treatment. Homogenizing and aging treatments could effectively eliminate elemental microsegregation, and the segregation ratios of all elements in niobium solid solution (Nbss) in different regions tend to 1. After heat-treatment, the microhardness of retained eutectic cells increases evidently, and the maximum value reaches HV1 404.57 for the specimen directionally solidified with a withdrawing rate of 100 μm/s and then heat-treated at (1 500 ℃, 50 h) + (1 100 ℃, 50 h), which is 72.8 % higher than that under DS condition.
Keywords:Nb-Ti-Si based ultrahigh temperature alloy  homogenizing treatment  aging treatment  microstructural evolution  microhardness  
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