基于最大m值法和恒应变速率法的Ti_3Al基合金超塑变形行为研究  

Superplastic Deformation Behavior of Ti_3Al Based Alloy Based on Maximum m Value and Constant Strain Rate Method

作　　者：付明杰[1] 许慧元[1] 刘佳佳[1] 韩秀全[1] 

机构地区：[1]北京航空制造工程研究所金属成形技术研究室,北京100024

出　　处：《材料工程》2015年第11期32-38,共7页Journal of Materials Engineering

摘　　要：分别采用最大m值法和恒应变速率法对Ti-24Al-15Nb-1.5Mo合金板材进行超塑拉伸,研究了940~1000℃、5.5×10-5~1.7×10-3s-1和不同拉伸轴方向的超塑性变形行为。结果表明：采用最大m值法获得的伸长率均高于恒应变速率法的,分别在980℃、垂直轧制方向获得了1596%的最大伸长率和960℃、3.3×10^-4s^-1、与轧制方向成45°获得了932%的伸长率。原始纤维组织经过超塑变形后发生等轴化,并且等轴晶粒随着应变速率的减小和温度的升高,长大程度逐渐增大。最大m值法超塑拉伸可以明显减少孔洞的产生。The superplastic deformation behavior of Ti-24Al-15Nb-1. 5Mo alloy with two different methods of based on maximum m value and constant strain rate was studied over the range of 940- 1000℃, 5.5×10-5~1.7×10-3s-1 and different tensile axis direction. The result shows that the maxi- mum superplastic elongation of maximum rn value is higher than that of the constant strain rate meth- od, and 1596% and 932% are obtained, respectively, at 980℃, Tdirectionand960℃, 3.3×10^-4s^-1, 45° to rolling direction, respectively. The elongated grain of primary microstructure will be trans- formed to equiaxed grain during superplastic tension and the equiaxed grain size increases with decrea sing of strain rate and increasing of deformation temperature. The maximum m value method can obvi- ously reduce the generation of cavities.

关 键 词：Ti3Al板材 超塑性 晶粒等轴化 孔洞 

分 类 号：TG146[一般工业技术—材料科学与工程]