钛合金片层α相在热加工过程中演变规律的定量研究(英文)  

Quantitative Analysis on Microstructural Evolution of Lamellar α Phase in Titanium Alloy during Hot Working

作　　者：王凯旋[1,2] 曾卫东[1] 赵永庆[2] 邵一涛[1] 周建华[3] 王晓英[3] 周义刚[1] 

机构地区：[1]西北工业大学,陕西西安710072 [2]西北有色金属研究院,陕西西安710016 [3]宝钢公司,上海200940

出　　处：《稀有金属材料与工程》2010年第4期565-569,共5页Rare Metal Materials and Engineering

基　　金：Key Foundational Research Plan of China(2007CB613807);Program for New Century Excellent Talents in University(NCET-07-0696);the Fund of the State Key Laboratory of Solidification Processing in NWPU(35-TP-2009)

摘　　要：对具有片层α相的Ti-17合金圆饼在两相区进行5种变形程度的等温锻造及固溶时效处理,用定量金相学方法研究了片层α相在热加工过程中的演变规律。研究发现:α相的厚度随着应变量的增大而增大;变形程度及圆饼的变形区域对α相形态的变化有很大影响。随变形程度的增大,α相的形态参数FeretRatio(Feretmax/Feretmin)的分布曲线在FeretRatio介于1.5～2.5区间出现单峰,且峰值不断增大,大FeretRatio的α相比例逐渐减小。圆饼中心位置的FeretRatio分布曲线具有较大的峰值。大变形使片层α相的等轴化程度提高,改善了圆饼的组织均匀性。等效应变对组织中不同形态α相分布的影响曲线表明:球化α相比例随着等效应变的增大呈单调增大,增大速率表现为慢—快—极慢的分阶段特征;近等轴状的α相比例先快速增长后不断减少;片层状和大片层状α相比例随着等效应变增大呈单调减少。片层α相的临界球化与完全球化的等效应变分别约为0.4与1.0。To quantitatively research the microstructural evolution of lamellar a phase in titanium alloys, large size cakes of Ti-17 alloy with initial lamellar microstructure were isothermally-forged at different strains in α＋β phase field followed by solid-solution and aging treatment. The changes of a thickness and morphology in different locations （center, midradius, edge） of the cakes deformed to different strain levels were measured and the imposed strain was estimated using finite element analysis. It is found that increasing of forging strains causes an increase in thickness of a phase. The modification of a morphology depends strongly on the forging strains and the locations in the cakes. The distribution curves of a morphology parameter Feret Ratio were characterized by no peak at lower strains, and a single peak appears at Feret Ratio 1.5-2.5 at larger strains. Moreover, the peak values increased with increasing of the height reduction, and the distribution curves at the center have the largest peak values. Increasing of forging strains will cause the high-Feret-Ratio lamellae to decrease but low-Feret-Ratio a to increase noticeably. Sufficiently imposed strains also can improve the microstructure homogeneity in different locations of the cakes. The effect of the effective strains on the percentage of a phase with different morphologies is also quantificationally summarized. The average strains for initiation of globalization are of the order of 0.4 and those for completion are of the order of 1.0, which are lower than that of conventional α＋β titanium alloys.

关 键 词：TI-17合金 片层α相 组织演变 定量研究 

分 类 号：TG146.23[一般工业技术—材料科学与工程]