粉末冶金高性能双态组织钛合金的制备  

Preparation of Powder Metallurgy Titanium Alloy with Bimodal Structure of High Mechanical Properties

作　　者：芦博昕 杨芳 周洋 陈存广 隋延力 郭志猛 Lu Boxin;Yang Fang;Zhou Yang;Chen Cunguang;Sui Yanli;Guo Zhimeng(Institute for Advanced Materials and Technology,University of Science and Technology Beijing,Beijing 100083,China;Shunde Graduate School of University of Science and Technology Beijing,Foshan 528399,China;Innovation Group of Marine Engineering Materials and Corrosion Control,Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519000,China)

机构地区：[1]北京科技大学新材料技术研究院,北京100083 [2]北京科技大学顺德研究生院,广东佛山528399 [3]南方海洋科学与工程广东实验室(珠海)海洋工程材料与腐蚀控制创新小组,广东珠海519000

出　　处：《稀有金属材料与工程》2022年第4期1152-1157,共6页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(52004027,U21A200305);Scientific and Technological Innovation Foundation of Foshan,USTB(BK21BE001);Fundamental Research Funds for the Central Universities(FRF-GF-20-05A);Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(311021013);State Key Lab of Advanced Metals and Materials(2020-Z17)。

摘　　要：采用氢化脱氢粉末,低温真空烧结法制备了相对密度为99%的粉末冶金Ti6Al4V合金。为了消除气孔并控制微观结构形态,对其进行了锻造。结果表明,锻造试样的显微组织为具有长板条初生α和α+β片层组织的双态结构。锻造后试样可以实现抗拉强度1176MPa,屈服强度1100 MPa,延伸率18.2%,同时具有良好的低周疲劳寿命。为了探索良好疲劳性能的原因,进行了原位疲劳观察试验。通过对裂纹扩展情况的观察,发现疲劳裂纹扩展可分为2个阶段:稳定阶段和加速阶段。致密组织减少了疲劳源在样品内部的产生。同时双态组织中的的长板条状初生α结构有效地阻止了稳态扩展阶段的疲劳裂纹扩展,从而延长了疲劳寿命。因此,双态结构表现出优异的综合力学性能。Powder metallurgy(PM)Ti6Al4V alloy with a relative density of 99%was prepared by low temperature vacuum sintering using fine Ti6Al4V powder.To eliminate porosity and control the microstructure morphology,forging was performed.The results show that microstructure of as-forged samples is bimodal structure with long lath primaryαandα+βlamellae.The as-forged samples show tensile properties with ultimate tensile strength(UTS)of 1176 MPa,yield strength(YS)of 1100 MPa,elongation(EL)of 18.2%,and good low-cycle fatigue life.The as-forged PM Ti6Al4V has good fatigue performance with more than 10^(5)cycles under the stress of 700 MPa.In order to explore the reasons for good fatigue properties,in-situ observation tests were carried out.It is found that the long lath primaryαstructure can effectively prevent the crack propagation in the steady propagation stage and prolong the fatigue life.Besides,fully dense structure decreases the fatigue crack initiation.Thus,the bimodal structure shows excellently comprehensive mechanical properties.

关 键 词：粉末冶金 TI6AL4V 双态组织 低周疲劳 原位观察 

分 类 号：TF125.22[冶金工程—粉末冶金]