摘要
采用Gleeble-3500热模拟压缩试验机对一种新型的β钛合金Ti-34521进行热模拟压缩实验,其应变速率为0.1-30s^(-1),变形温度为750-1000℃,压下量为50%,并采用光学显微镜和电子背散射衍射(EBSD)技术对变形后的微观组织进行表征,研究了该合金高温变形过程中的微观组织演变机制。结果表明:变形后合金的β晶粒沿着垂直于压缩方向被压扁,并形成了<001>和<111>变形丝织构。随着变形温度的升高和应变速率的降低,β晶粒的动态回复(DRV)和动态再结晶(DRX)逐渐增强,且晶界弓出行为和生成的DRX晶粒使得β晶界呈现出锯齿状和项链状形貌。最后,讨论了合金的微观组织演变和力学行为之间的关系,发现当应变增大到0.4以后,合金的表观变形激活能为221.533-201.207 kJ/mol,该值与β-Ti自扩散激活能相近,这是由于动态回复是合金变形过程中的主要动态软化机制所致。
Thermal simulation compression experiment of a new type of β titanium alloy Ti-34521 was carried out by using a Gleeble-3500 thermal simulation compression tester under the deformation condition of strain rates of 0.1-30s^(-1), deformation temperature of 750-1000 ℃ and height reduction of 50%, and microstructure of the alloy after deformation was characterized by optical microscope and electron backscatter diffraction(EBSD) technique in order to study the microstructure evolution mechanism of the alloy during the high temperature deformation. The results show that the β grains of the alloy after deformation are elongated along the direction perpendicular to compression, and the deformed<001>and<111>fiber texture is formed. The increase of deformation temperature and the decrease of strain rate promote the dynamic recovery(DRV) and dynamic recrystallization(DRX) of the β grains, and the grain boundary bulging and the generation of DRX grains make the β grain boundaries show the serrated and necklace-like morphology. Finally, the relationship between microstructure evolution and mechanical behavior of the alloy is discussed, and it is found that when the strain increases to 0.4, the apparent deformation activation energy of the alloy is 221.533-201.207 kJ/mol, which is similar to the self-diffusion activation energy of β-Ti, becasue the dynamic recovery is the main dynamic softening mechanism in the deformation process of the alloy.
作者
王柯
黎东荣
辛仁龙
郭艳华
常辉
刘庆
WANG Ke;LI Dong-rong;XIN Ren-long;GUO Yan-hua;CHANG Hui;LIU Qing(School of Materials Science and Engineering,Chongqing University,Chongqing 400044,China;College of Materials Science and Engineering,Nanjing Tech University,Nanjing 211816,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2021年第7期49-56,共8页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51971046)
中央高校基本科研业务费(2020CDJGFCL005)。
关键词
Β钛合金
高温变形
微观组织
动态再结晶
β titanium alloy
hot deformation
microstructure
dynamic recrystallization
