热处理对高Nb-TiAl合金板材组织及力学性能的影响  

Effect of Heat Treatment on Microstructure and Mechanical Properties of High Nb-TiAl Alloy Sheet

作　　者：沈正章 梁永锋[1] 王艳丽[1] 郝国建[1] 张来启[1] 林均品[1] 

机构地区：[1]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《材料研究学报》2015年第9期649-655,共7页Chinese Journal of Materials Research

基　　金：国家重点基础研究发展计划2011CB605501资助项目~~

摘　　要：研究了不同热处理工艺对高Nb-TiAl合金板材的显微组织及力学性能的影响。采用铸锭原料直接包套热轧制备的板材主要由残余粗化的片层团、再结晶γ晶粒和沿轧制方向带状分布的β相组成。通过不同的热处理工艺可以消除残余片层和β相,分别获得典型的双态组织、近片层组织和全片层组织。对热处理后具有双态组织的板材进行了室温和高温力学性能测试,结果表明:经热处理后,热轧板材的室温延伸率达到0.5%,屈服强度和抗拉强度分别提高到646MPa和691MPa,与铸态相比,其室温强度和塑性得到了改善,在850-900℃之间材料发生韧脆转变,并且相应断裂机理从脆性的穿晶断裂转变为孔洞的形核和聚集。Effect of heat treatment on the microstructure and mechanical properties of a high Nb-containing TiAI alloy sheet was investigated, which was fabricated by directly hot-rolling a packed alloy ingot. The obtained sheet mainly consisted of remnant coarsening lamella, recrystallized γgrains and strip-like β phase along rolling direction. Followed by variant heat treatments, the coarse lamella and β phase were eliminated, and various typical microstructures were appeared, such as duplex, near fully lamellar and fully lamellar ones. Mechanical properties of the sheet with duplex microstructure were tested at room and high temperatures respectively. The results showed that the strength and ductility of the sheet at room temperature were improved after heat treatment. The brittle-ductile transition temperature was in the range of 850-900℃, and the corresponding fracture mode transformed from transgranular fracture to the nucleation and coalescence of voids.

关 键 词：金属材料 高Nb—TiAl合金 包套热轧 热处理 双态组织 力学性能 

分 类 号：TG146[一般工业技术—材料科学与工程]