Effects of Large Deformation Near-isothermal Forging on Microstructures and Properties of TiAl Alloy
SI Jia-yong1, LI Sheng2, ZHANG Ji2
1. College of Mechanical & Electrical Engineering,Central South University of Forestry & Technology,Changsha 410004,China;
2. High Temperature Material Research Institute,Central Iron & Steel Research Institute,Beijing 100081,China
Abstract：The effects of increasing deformation strain on the microstructure uniformity and mechanical property stability of Ti-46.5Al-2.5V-1.0Cr-0.3Ni alloy were quantitative studied by single near-isothermal forging. The observed microstructure and measured hardness and strength can revealing the basic relationship among deformation strain, macrostructure and microstructure. The results show that distribution of flow lines is more uniform and the area of uniform zone is enlarged with the engineering strain raised from 65%, 70%, 75%, 80% to 85%. In the forged pancake, the proportion of uniform zone expand to 68.0％ when the strain is 85%. And the deformation microstructure is composed by equiaxed γ,α2 and a few remnant laminas. The grain dimension is obviously refined and the vast majority is equiaxial microstructure. The hardness testing shows that hardness of uniform zone is tending to be uniformity and the average hardness is continuous to increase. The room temperature compression samples were machined from stagnant zone and uniform zone with heat treatment at 1250℃/15h/AC. The dispersity of room temperature compression results is reduced and it means that property stability is improved with the increased engineering strain.
司家勇, 李胜, 张继. 大变形量近等温锻造开坯对TiAl合金组织与性能的影响[J]. 材料工程, 2013, 0(6): 40-44.
SI Jia-yong, LI Sheng, ZHANG Ji. Effects of Large Deformation Near-isothermal Forging on Microstructures and Properties of TiAl Alloy. Journal of Materials Engineering, 2013, 0(6): 40-44.
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