The Influences of Heat Treatment on the Microstructure and Mechanical Properties of Rolled Ti2AlNb

Abstract

In this study, the microstructural evolution, distribution, morphology, and change mechanism of an as-rolled Ti2AlNb alloy were quantitatively analyzed by X-ray diffraction and electron backscatter diffraction (EBSD). The results show that after solution treatment at 900 °C, the content of the O phase alloy decreased by 2%, which provided space for the nucleation of the α2 phase, the content of which increased by 2%. After aging treatment at 760 °C, large quantities of acicular O phase and α2 phase were precipitated in the B2 matrix, and the content of the α2 phase increased. As the aging temperature increased to 840 °C, the elongated α2 phases were connected to each other at a specific angle along the grain boundary, extending to the interior of the grain. The hardness reached its maximum value of 402 HV at 760 °C. This study deepened our understanding of the formation of the α2 phase in the microstructure of rolled Ti2AlNb alloy, and investigates the effect of α2 phase content on the hardness of the alloy in more depth.