Influence of Heat Treatment on Microstructure of Laser Solid Forming Ti-6.5Al-3.5Mo-1.5Zr-0.25Si Alloys
Huang Yu1,2, Chen Jing1, Zhang Fengying1, Lin Xin1, Huang Weidong1 (1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China) (2. Northwest Institute for Nonferrous Metal Research, Xi’an 710016, China)
The as-deposited microstructure and heat-treated microstructure of Ti-6.5Al-3.5Mo-1.5Zr-0.25Si alloys (TC11) by Laser Solid Forming (LSF) were compared, and approaches to improve LSF microstructure and high-temperature combination properties of TC11 alloys were researched. Results show the as-deposited microstructure of TC11 alloy consists of coarse columnar grains and equiaxed grains throughout cladding layers, and the prior columnar β-Ti grains are composed of lathlike α and residual β. The microstructure of as-deposited samples after 950 ℃ heat treatment is a similar triplex mixture of equiaxed α, basketweave α lath and transformed β. The majority of continuous prior α boundary is broken, and become spheroidized and illegible; α laths grow up to bunch on some unbroken boundary; the equiaxed α in coarse β grains is related with subgrains. The microstructure after heat treated at 970 ℃ is a certain basketweave structure consisting of a few equiaxed-α and α laths which have coarsening tendency; the microstructure after recrystallization at 1030 ℃ followed by 950 ℃ heat treatment is typical Widmanst?tten structure consisting of coarse α laths, and lots of β-Ti is found to separate out inside α and on α boundaries without breaking basically.
【CateGory Index】： TG146.23