Designing a hybrid microstructure of Ti-43Al-9V-0.3Y alloy and its non-equilibrium phase transition mechanism via two-step forging

作     者：Yuan Ye Yu Zhang Shuzhi Zhang Yuyong Chen Jianfei Sun Yuan Ye;Yu Zhang;Shuzhi Zhang;Yuyong Chen;Jianfei Sun

作者机构：School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China School of Materials Science and EngineeringYanshan UniversityQinhuangdao 066004China The National Key Laboratory for Precision Hot Forming of MetalsHarbin 150001China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术(英文版))

年 卷 期：2024年第192卷第25期

页      面：251-264页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：The authors are grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.52201116,52301143,52071228,and 52271118) the State Key Labo-ratory of Advanced Welding and Joining,Harbin Institute of Tech-nology(Grant No.AWJ-23M24) the Heilongjiang Provincial Natural Science Foundation of China(Grant No.YQ2023E007) 

主　　题：TiAl alloy Hybrid microstructure Lamellar structures Non-equilibrium phase transition Two-step forging 

摘      要：Understanding the non-equilibrium phase transition mechanism is critical to controlling the transform-ing microstructures and thus material *** order to improve the problem of low room-temperature ductility of TiAl alloys with traditional microstructures,a two-step forging with an interme-diate heat preservation process is proposed to prepare a hybrid microstructure via non-equilibrium phase transition in this *** hybrid microstructure is composed ofβ_(0)/γlamellar colony,a structure with innerα_(2)/γand outerβ_(0)/γlamellae surrounded byβ_(0)phase,a structure ofγgrains embedded withinα_(2)/γlamellar colony,and some granularβ_(0)withinγ*** hybrid microstructure exhibits excellent room-temperature mechanical properties with a total elongation to failure of 2.15%and tensile strength of 920 ***,the evolution mechanisms of these various structures are analyzed from the perspective of solute element diffusion and distribution in front of the phase transition ***-gation of V element in front of theγgrowth interface induces the elemental reaction deviating from the equilibrium phase transitionα→α_(2)+γ,andα→β(β_(0))+γtransition occurs,resulting in the formation ofβ(β_(0))/γlamellar *** hot forging,α→α_(2)+γtransition occurs to generateα_(2)/γlamellae in the initial transition stage(I)of solute *** the stable stage(II),the content of V element in front of the growth interface ofγlamellae increases to∼18.41%,andα→β(β_(0))+γtransition occurs,soβ(β_(0))/γlamellae are formed outside theα_(2)/γlamellar *** the final stage(III),the remainingαphase is less,and the diffusion of the V element is hindered,causing a sudden increase of the V element inαphase,resulting in the remainingαphase transformed into irregularβ(β_(0))***,the structure with innerα_(2)/γand outerβ_(0)/γlamellae surrounded byβ_(0)phase is ***,adjusting the cooling rate realizes the precise controlling of theα_(2)/γ,β_(0)