(南昌航空大学 航空制造工程学院 轻合金加工科学与技术国防重点学科实验室,南昌 330063)
摘 要: 对TA15合金在拉伸试验机上进行应变速率敏感因子( 值)高效超塑性变形试验,研究合金的超塑性性能和显微组织。结果表明:在780~950℃变形时,TA15合金呈现出良好的超塑性能;900 ℃变形时,该合金的超塑性能最好, 值达到0.62,最大伸长率为1287%;随着变形温度的升高,合金的超塑性能降低,950 ℃时伸长率仅为567%。显微组织分析表明:TA15合金在超塑性变形过程中,晶粒始终保持等轴状;由于变形温度升高,晶粒合并长大,950 ℃时发生 → 相转变,初生 相体积分数大幅度降低。与最大 值法相比较, 值高效超塑性变形不仅使TA15合金获得了良好超塑性能,变形效率也显著提高。
关键字: TA15合金;超塑性; 值;显微组织
(National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology,
School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China)
Abstract:The high efficient superplastic deformation experiments of TA15 alloy based on m value were performed on the tensile testing machine. The superplastic properties and microstructure were studied. The results indicate that TA15 alloy exhibits excellent superplasticity at temperatures of 780-950 ℃. The superplasticity is the best at 900 ℃. The m value is 0.62 and the maximum elongation is 1287%. With temperature increases, the superplasticity decreases and the elongation is only 567% at 950 ℃. The microstructure analysis shows that the equiaxed grains are kept during deformation. The grains merge and grow up due to increasing temperature. The volume fraction of primary phase decreases greatly because → phase transformation occurs at 950 ℃. Compared with the method of maximum m value, not only the excellent superplasticity of TA15 alloy is obtained by the high efficient superplastic deformation, but also the deformation efficiency is enhanced obviously.
Key words: TA15 alloy; superplasticity; m value; microstructure