Ti-6Al-4V钛合金多工序加工的微观结构和力学性能研究（英文）  

Microstructures and Mechanical Properties of Ti-6Al-4V Alloy Processed by Multi-Process

作　　者：汪程鹏[1] 李付国[1] 肖美立[1] 董俊哲[1] 李景辉[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》2015年第4期838-843,共6页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(51275414);Aeronautical Science Foundation of China(2011ZE53059)

摘　　要：为获得环轧、胀形和热处理不同工艺组合状态下Ti-6Al-4V合金加工工艺-力学性能-微观组织之间的关系,分别对其α相和β相组织形貌,室温和高温拉伸性能(强度和塑性)进行观察与分析。研究表明,在适当的热处理工艺下,合金轧制成形之后增加第二工序胀形是很有必要的。材料的拉伸性能与初生α相的晶粒尺寸和体积分数,及次生α相的晶粒尺寸和组织厚度有很大关系。此外,胀形后热处理主要影响初生α相的晶粒尺寸及α相和β相组成比例,其次影响次生片状α相的大小和数量。当α相由小颗粒等轴组织转变为厚的多边形状组织时,材料的延伸率降低。随着初生α相体积分数的减少,未转变β相组织和弥散次生α相的增加,合金强度增加。材料高温拉伸断裂为韧性断裂,材料低塑性归因于组织断裂表面铸造微缺陷的萌生。To understand the relationship among the processes, mechanical properties and microstructures of the Ti-6A1-4V alloy processed by the different combinations of ring rolling, bulging and different heat treatments, the correlation between the a- and β-phase morphologies, the strength and plasticity properties of tensile tests at ambient temperature and elevated temperature were investigated. Researches indicate that adding the second procedure, bulging, is necessary after the rolling process under the condition of the appropriate heat treatment. The tensile properties are closely related to the size and the volume fraction of the primary a-phase, the size and the thickness of the secondary a-phase. Furthermore, the bulging after heat treatment mainly affects firstly the size of primary a-phase, and the compositions of a- and β-phase, secondarily the size and the quantity of the secondary platelet a-phase. The elongation decreases when the primary a-phase transforms from the small equiaxed to the thick multilateral shape. As the volume fraction of the primary a-phase decreases and the proportions of both untransformed β structure and the dispersed secondary a-phase increase, the alloy strength increases. Fracture modes of the elevated temperature tensile fracture samples were determined as the ductile fracture. Poor plastic deformation ability is attributed to the casting micro-defects on the fracture surface.

关 键 词：TI-6AL-4V合金 加工 机械性能 微观组织 断裂 

分 类 号：TG146.23[一般工业技术—材料科学与工程]