原位TiC颗粒对喷射沉积7075铝合金热变形行为的影响

Effect of in-situ TiC particles on hot deformation behavior of spray formed 7075 Al alloy

采用原位反应喷射沉积法制备7075+4.4%TiC铝合金,在Gleeble-1500热模拟机上进行热压缩变形实验。获得7075+4.4%TiC铝合金在不同变形条件下的真应力-真应变曲线和微观组织,并与相同条件下的喷射沉积7075铝合金作对比,研究原位TiC颗粒对喷射沉积7075铝合金热变形行为的影响。结果表明,喷射沉积7075和7075+4.4%TiC铝合金热变形过程中流变应力随变形温度的增加而下降,当应变速率降到0.001 s-1后,发生动态再结晶现象。原位TiC颗粒对喷射沉积7075铝合金的真应力-真应变曲线、动态再结晶温度没有显著影响,但是对再结晶晶粒长大行为具有明显的抑制作用。

The hot deformation behavior of in-situ reactive spray formed 7075 + 4. 4% TiC Al alloy and spray formed 7075 Al alloy was studied by isothermal compression test on a Gleeble-1500 thermal-mechanical simulator. As-spray formed microstructure of 7075 Al alloy and 7075 + 4. 4% TiC Al alloy was observed using SEM. The dynamic recrystallization mechanism during hot compression was examined using OM and the true stress-strain curves. The results show that the flow stress decreases with the increase of deforming temperature,and the dynamic recrystallization occurs at the strain rate of 0. 001 s-1. The influence of in-situ TiC particles on true stress-strain curve and dynamic recrystallization temperature of spray formed 7075 Al alloy is not evident. However,the recrystallization grain growth is restrained significantly by the in-situ TiC particles.