电弧熔炼Nb-Ti-Cr-Si基超高温合金的组织和室温力学性能  

Microstructure and Ambient Mechanical Properties of Nb-Ti-Cr-Si Based Ultrahigh Temperature Alloy by Consumable Arc Melting

作　　者：郭宝会[1] 郭喜平[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属材料与工程》2013年第7期1387-1392,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金资助(51071124);高等学校博士点基金项目(20096102110012);陕西省科学计划项目(2012JM6019)

摘　　要：采用真空自耗电弧熔炼法制备了Nb-Ti-Cr-Si基超高温合金合金锭,测试了其室温力学性能。结果表明:合金锭各位置处的成分除Cr元素外分布比较均匀,Cr元素从锭边缘到中心部分呈现减少的趋势。合金的显微组织主要由初生Nbss,呈片层状或花瓣状的Nbss/(Nb,X)5Si3共晶组织及细小的Nbss/Cr2Nb共晶团组成,但在合金锭顶部中央处还出现了少量的块状(Nb,X)3Si。随着离锭边缘距离的增加,初生Nbss枝晶杆由细变粗,Nbss/(Nb,X)5Si3共晶组织的定向效果逐渐消失,但Nbss/Cr2Nb共晶团体积分数有减小的趋势。经过多元合金化的Nb-Ti-Cr-Si基合金室温的抗拉强度为378.7MPa,室温断裂韧性为13.4MPa·m1/2。室温拉伸和断裂韧性试样的失效模式均为脆性准解理断裂。The ingot of Nb-Ti-Cr-Si based ultrahigh temperature alloy was prepared by vacuum consumable arc melting, and the ambient mechanical properties of the alloy were measured. The results show that the chemical components are distributed uniformly at different positions of the master alloy except Cr whose concentration in the central of the ingot top is lower than that of other positions. The microstructure of the ingot is mainly composed of primary Nbss dendrites, Nbss/（Nb, X）5Si3 eutectic which exhibit typically lamellar or petal-like morphologies, and fine Nbss/CrENb eutectic colonies. However, some （Nb, X）3Si are present at the top of the ingot alloy. The primary Nbss becomes coarser and directionally solidified character of Nbss/（Nb, X）5Si3 eutectic colonies disappear gradually from the edge to the central of the_ingot. The volume of the fine Nbss/Cr2Nb eutectic colonies is reduced. The ambient tensile strength reaches 378.7 MPa, and the ambient fracture toughness is about 13.4 MPa·m^（1/2） for the Nb-Ti-Cr-Si alloy. In addition, ambient fracture mechanism is characterized by brittle quasicleavage mode in both fracture and tensile morphology.

关 键 词：Nb-Ti-Cr-Si基超高温合金 显微组织 相组成 室温力学性能 

分 类 号：TG132.32[一般工业技术—材料科学与工程]