Effect of heat treatment and thermomechanical processing on microstructure and tensile property of Ti-44Al-8Nb-0.2W-0.2B-0.5Y alloy  

作　　者：Xiao-peng Wang Fan-tao Kong Xiao-ping Cao Shu-zhi Zhang Chang-jiang Zhang Yu-yong Chen 

机构地区：[1]Center of Analysis and Measurement,Harbin Institute of Technology,Harbin 150001,China [2]National Key Laboratory for Precision Hot Processing of Metals,Harbin Institute of Technology,Harbin 150001,China [3]School of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China

出　　处：《China Foundry》2020年第6期447-454,共8页中国铸造（英文版）

基　　金：the National Natural Science Foundation of China(Project Nos.:51971074,51471056);the State Key Laboratory for Advanced Metal and Materials Foundation(Project No.:2013-ZD06);the National Basic Research Program of China(Project No.:2011CB605502)。

摘　　要：High Nb-TiAl (Ti-44Al-8Nb-0.2W-0.2B-0.5Y,at.%) ingot was fabricated by vacuum arc remelting (VAR).The as-cast ingot was hot-isostatic pressed (HIP) and homogenizing annealing processed.The influence of heat treatment temperature and thermomechanical processing on the microstructure and tensile property of the alloy was investigated by X-ray diffractometry (XRD),scanning electron microscopy (SEM) and tensile tests.It was found that the high Nb-TiAl alloy after HIP and annealing was mainly composed of coarse α2/γ lamellae,β/B2 phase and γ phase and the solidification path of this alloy was:L→L+β→β→α+β→α→α+β+γ→α2+β+γ.The water quenching results showed that the alloy was in α single phase region at 1,340 °C.After heating at 1,340 °C for 30 min followed by furnace cooling,the alloy showed a full lamellar microstructure and its ultimate tensile strength was about 538 MPa,with an elongation of 0.3% at room temperature.Free-crack forged pancakes with fine-grained fully lamellar structure (FFLS) were obtained with an initial deformation temperature of 1,340 °C and the ultimate tensile strength of forged alloy was about 820 MPa,with an elongation of 0.9% at room temperature,which was much higher than that of alloy after HIP and annealing because of microstructural refinement.

关 键 词：high Nb-TiAl alloy heat treatment MICROSTRUCTURE tensile property 

分 类 号：TG146.23[一般工业技术—材料科学与工程]