Effect of Al_(2)O_(3)fiber on twin intersections-induced dynamic recrystallization in fine-grained TiAl matrix composite  

作　　者：Yaofeng Luo Yan Wang Li Wang Bin Liu Yong Liu 

机构地区：[1]State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China

出　　处：《Journal of Materials Science & Technology》2024年第5期1-14,共14页材料科学技术（英文版）

基　　金：the National Science and Technology Major Project(No.2019700160157);the Natural Science Foundation of Hunan Province(No.2021JJ40761);the Central South University Innovation-Driven Research Programmme(No.v2023CXQD030);the Independent Innovation Fund Project Aero Engine Corporation of China(No.CXPT-2021-001);the Postgraduate Scientific Research Innovation Project of Hunan Province(No.CX20230163);the Fundamental Research Funds for the Cen-tral Universities of Central South University(No.2023ZZTS0078)for providing financial support.

摘　　要：Dynamic recrystallization(DRX)is of great significance for the thermomechanical processing and microstructural regulation of TiAl intermetallics.However,the underlying DRX mechanism remains poorly understood.In this study,an Avrami kinetics model for DRX was established,which was capable of predicting the DRX fraction accurately.In addition,the effect of Al_(2)O_(3)short fiber on the DRX mechanisms of TiAl matrix composite during the isothermal compression was investigated for the first time.The re-sults showed that other than inhibiting DRX by particles in the TiAl matrix composites,the addition of Al_(2)O_(3)short fiber accelerated a novel DRX process,which was induced by twinning and twin intersec-tions(TDRX).Thus,this composite exhibited a higher DRX rate than that of the as-cast TiAl monolithic alloy.The origin of the twin intersection and TDRX for the composite was revealed.The stress concentration near the Al_(2)O_(3)fiber was above the critical shear stress for twinning and thus was favorable for the formation of twinning and twin intersections.The high stored strain energy at the regions of twins and twin intersections provided the driving force for TDRX.TDRX accelerated the grain refinement in the TiAl matrix near the Al_(2)O_(3)fiber.The present findings would provide a new perspective on DRX mechanisms,and provide the scientific guidance for optimizing the microstructures of TiAl matrix composites.

关 键 词：TiAl matrix composite Al_(2)O_(3)fiber Twin intersection Dynamic recrystallization 

分 类 号：TG1[金属学及工艺—金属学]