Ti_2AlNb合金粉末冶金件的热变形行为和环轧过程的模拟研究  

Simulation Study on Hot Deformation Behavior and Ring Rolling Process of PM Ti_2AlNb Alloy

作　　者：卢正冠 吴杰[1] 刘羽寅[1] 徐磊[1] 

机构地区：[1]中国科学院金属研究所,辽宁沈阳110016

出　　处：《钛工业进展》2016年第4期31-35,共5页Titanium Industry Progress

摘　　要：采用粉末冶金热等静压工艺制备了Ti_2AlNb合金坯料,为研究其开坯行为,采用Gleeble-3800热机械模拟试验机进行了热压缩试验,另外采用Simufact有限元软件模拟了粉末冶金Ti_2AlNb合金的环轧过程,利用X射线三维成像技术获取并计算了第一次环轧后的孔隙分布。结果表明,粉末冶金Ti_2AlNb合金在应变极小时达到峰值应力,在变形初始阶段应力水平的变化不稳定。压缩变形后样品晶粒内O相板条结构消除,晶界处α2相发生长大偏聚,变形条件引起的粉末冶金Ti_2AlNb合金的相转变是影响开坯行为稳定性的主要原因。开坯阶段环件边缘处的温降和应变增长速率最快。变形可以愈合粉末冶金Ti_2AlNb合金的孔隙。Powder metallurgy （PM） Ti2AlNb alloy billet was prepared by hot isostatic pressing route. To study the blooming behavior of PM Ti2AlNb alloy, high temperature compression tests were conducted on Gleeble-3800 thermal- mechanical simulation testing machine. Besides, Simufact finite element （FE） software was also used to simulate the ring rolling process of PM Ti2AlNb alloy, and X-ray Micro Computed Tomography （Micro-CT） method was used to study the pore distribution in actual rolled PM TizAlNb ring. Results show that the flow stress of PM Ti2AlNb alloy reaches to the peak value at a small strain, and is unstable at the beginning process. After compression, O laths inside grain in deformed samples disappear and the presence of a2 phase growth and segregation at the grain boundaries are observed. The phase transformation caused by the changed deformation conditions is the main reason for the flow instability during deformation. The temperature drops and effective strain at the edge of ring increases rapidly, and the deformation is helpful to reduce the porosity of PM Ti2AlNb alloy.

关 键 词：Ti2AlNb合金 粉末冶金 热变形 环轧 

分 类 号：TF125.22[冶金工程—粉末冶金] TG339[冶金工程—冶金物理化学]