大变形轧制加工条件下纯钛的动态再结晶行为

Dynamic recrystallization behavior of pure titanium under severe deformation hot-rolling

采用两种工艺方案进行纯钛棒材大变形轧制试验:850℃高温连续大变形轧制;760℃低温大变形轧制,并辅以轧制道次间10 s左右的短时停顿。研究了两种不同工艺条件下纯钛的动态再结晶行为。结果表明,两种轧制方式的纯钛显微组织差异明显:经过工艺1加工后的纯钛横截面组织差异大,表层及心部组织细小、均匀,近表面出现粗晶过渡区域,低倍下呈现蝶状轮廓;经工艺2加工后的纯钛横截面晶粒尺寸较大,近表面粗晶区域小,低倍蝶状轮廓消失。

Two kinds of severe deformation hot-rolling processes were used to prepare pure titanium bar. One is the continuous severe deformation hot rolling at 850 ℃; another is severe deformation at 760 ℃ together with 10 s pause between the passes. Dynamic recrystallization behavior of pure titanium under both kinds of different processes were investigated. The results show that the microstructure is different for two hot-rolling processes. After hot-rolling by the process 1, the tested pure titanium exhibits different mierostructure between the inside and the outside of bar. The grain size is fine and uniform in the surface and core. There is a coarse-grain area near the surface of the bar, showing the ＂butterfly-like＂ macrostructure. The pure titanium roiled by the process 2 shows the more coarse grain size. The coarsegrain area near the surface of the bar is small and the ＂butterfly-like＂ macrostructure disappears.