全片层与双态组织高铌TiAl合金高温原位拉伸研究  

In-situ Tensile Study for Fully Lamellar and Duplex Microstructures of High Nb Containing TiAl Alloys at Elevated Temperature

作　　者：焦泽辉[1,2,3] 宋西平[4] 张敏[4] 于慧臣[1,2,3] 

机构地区：[1]北京航空材料研究院航空材料检测与评价北京市重点实验室,北京100095 [2]北京航空材料研究院先进高温结构材料重点实验室,北京100095 [3]中航试金石检测科技有限公司,北京100095 [4]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《材料工程》2013年第9期79-83,90,共6页Journal of Materials Engineering

基　　金：国家'973'计划项目(2011CB605506)

摘　　要：利用原位观察的方法研究了全片层(Fully Lamellar,FL)组织与双态(Duplex,DP)组织高铌TiAl合金在750℃下的拉伸力学行为。结果表明:DP组织具有较好的抗拉强度和塑性,其抗拉强度为958MPa,断面收缩率为45.1%,FL组织抗拉强度较低且几乎没有塑性;随着拉伸应力的增加,DP组织合金试样表面存在一个大量裂纹萌生和扩展的过程,这些裂纹均匀分布在试样表面,主要以萌生为主,几乎难以扩展,而在FL组织中只能观察到少量的裂纹萌生现象;拉伸断裂后的DP组织合金的裂纹是由多个孔洞合并而成,呈蠕虫状且尺寸很小,FL组织中与拉伸方向垂直或呈一较大夹角的片层团界及片层界较易萌生裂纹,在临近断口区域,裂纹主要以穿层扩展为主。The high Nb containing TiA1 alloys with fully lameUar （FL） and duplex （DP） microstruc tures were investigated based on the in-situ tension tests at 750℃. The results show that DP has bet- ter tensile strength of 958MPa and area reduction of 45.1%. FL has lower tensile strength and little ductility. The microcracks initiation and propagation occur on DP specimen surface. The amount of microcracks increases and the microcracks widely distribute with the increasing loading. The microc- racks hardly grow after initiation. There are a small number of microcracks observed on FL specimen surface. For DP structure, the vermiculated cracks form through the coalition of small holes. For FL structure, microcracks initiate along interlamellar and colony boundaries, being perpendicular or a large angle to the loading axis. But near the fractured location, it is the translamellar propagation cracks that result in the rupture.

关 键 词：高铌TIAL合金 全片层组织 双态组织 原位拉伸 

分 类 号：TG146.2[一般工业技术—材料科学与工程]