Abstract
Dynamic recrystallization(DRX)is of great significance for the thermomechanical processing and mi-crostructural 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 pre-dicting the DRX fraction accurately.In addition,the effect of Al2O3 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 Al2O3 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 concentra-tion near the Al2O3 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 Al2O3 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.
基金项目
National Science and Technology Major Project(2019700160157)
Natural science Foundation of Hunan Province(2021JJ40761)
Central South University Innovation-Driven Research Programmme(v2023CXQD030)
Independent Innovation Fund Project Aero Engine Corporation of China(CXPT-2021-001)
Postgraduate Scientific Research Innovation Project of Hunan Province(CX20230163)
Fundamental Research Funds for the Central Universities of Central South University(2023ZZTS0078)
NETL
NSTL
万方数据