TC4钛合金降温压缩变形行为

Behavior of cooling compression for TC4 titanium alloy

研究了TC4钛合金不同应变速率和降温速率时降温压缩过程的流变行为,发现降温压缩瞬时温度下的材料流动应力低于相同温度下的恒温压缩流动应力。经过XRD检测方法分析不同热和变形历史条件下试样的相含量得出,虽然降温和变形过程都促进了β相向α相的转变,但由于降温压缩试样的初始温度较高,变形后其β相的含量高于相同温度的恒温压缩试样,导致降温压缩流动应力较低。通过引入降温影响因子改进了混合物法则,准确地表征了降温过程流动应力与相含量之间关系。

Non-isothermal compression tests of TC4 were investigated at different strain rates and cooling rates. The results show that the flow stress under a certain temperature during the non-isothermal compression is lower than that of the isothermal compression under the same temperature. The phase content of the deformed sample was detected by using the XRD method. Although both of the cooling and deformation process contribute to the transformation of β toward α, because of the higher initial temperature during the non-isothermal compression, the content of β phase in the non-isothermal compression samples is higher compared to that in the isothermal compression, which causes the lower flow stress of the non-isothermal compression sample. A cooling factor is added into the mixture rule which makes it accurately explain the relationship between the cooling process flow stress and phase content.