Deformation and phase transformation behaviors of a high Nb-containing TiAl alloy compressed at intermediate temperatures  

作　　者：Xu Liu Lin Song Andreas Stark Uwe Lorenz Zhanbing He Junpin Lin Florian Pyczak Tiebang Zhang 

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China [2]Institute of Materials Research,Helmholtz-Zentrum Geesthacht,Max Planck-Str.1,Geesthacht 21502,Germany [3]State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China

出　　处：《Journal of Materials Science & Technology》2022年第7期89-96,共8页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 51971175);the Natural Science Basic Research Plan of Shaanxi Province (No. 2020JM-097);the State Key Laboratory of Solidification Processing (No. 2021-TS-05);the State Key Laboratory of Advanced Metals and Materials (No. 2020-ZD03);the “111” Project (No. B20028)。

摘　　要：In modernβ-solidified TiAl alloys,the decomposition of α_(2) phase is frequently observed during heat treatment or high-temperature deformation of the alloys.In this study,high-temperature deformation and decomposition mechanisms of α_(2) phase in a Ti-45Al-8.5Nb-0.2B-0.2W-0.02Y alloy are investigated.In a sample deformed at 800℃,the precipitation ofβ_(o)(ω_(o))phase is observed within the equiaxed α_(2) phase.The nucleation ofω_(o) particles within theβ_(o) matrix indicates the α_(2)→β_(o)→ω_(o) transformation.In addition,numerous y phase precipitates form within theβ_(o)(ω)areas.The α_(2) lamellae decompose into ultrafine( α_(2)+γ)lamellae and coarsened y lamellae via α_(2)→ α_(2)+γand α_(2)→γtransformation,re-spectively.Moreover,theω_(o) phase nucleates within the ultrafine lamellae via α_(2)→ω_(o) transformation.However,in a sample deformed at 1000℃,the nucleation ofβ_(o) particles is sluggish,which is caused by the efficient release of the internal stress via dynamic recrystallization(DRX).These results indicate that complex phase transformations can be introduced by the decomposition of α_(2) phase in TiAl alloys with a high amount ofβ-stabilizing elements.

关 键 词：TiAl alloys Phase transformation Microstructure Electron microscopy 

分 类 号：TG146.23[一般工业技术—材料科学与工程]