基于定量金相学的TC17钛合金片层组织取向行为分析

基于定量金相学原理,结合有限元模拟技术,定量研究了TC17钛合金在等温锻造过程中片层α取向随应变量的变化规律。分析发现:当应变量小于0.38时,片层α的取向呈对称双峰分布,两峰值之间夹角约为60°,表明片层α具有择优取向,微观组织保持原始的网篮特征;随着应变量的增大,片层α的取向分布出现不对称双峰现象,某一峰值取向参数角的体积分数变大,两峰值之间的夹角变小,网篮组织被不同程度的打碎;当应变量达到0.77左右,片层α取向呈近似单峰分布,取向参数角在80°～90°附近的体积分数达到最大,片层α趋向垂直于压缩轴分布。

Quantitative Analysis of the Orientation of Lamellar a in TC17 Titanium Alloy

The orientation distribution of lamellar alpha in TC17 alloy was studied using quantitative metallography approach and finite element simulation.It is found that the orientation distribution of lamellar α varies with the value of strain.As the result,when the value of strain is below 0.38,the orientation distribution presents two symmetrical peaks,and the angle between the peaks is 90°,which indicates that lamellar α has a preferential orientation,and the microstructure shows a good agreement with initial lamellar microstructure.With the increase of strain,two asymmetric peaks appear in the orientation distribution of lamellar α,the volume fraction of lamellar α of one orientation peak increases and the angle between the peaks decreases.Initial basket structure is broken to different degree.When the value of the strain reaches about 0.7,the orientation approximately tends to present single-peak distribution with the preferential orientation of 80°～90°,lamellar α almost perpendicular to the direction of compression was observed.