置氢处理对铸态TiZrAlV合金高温变形行为及显微组织的影响

Effect of hydrogenated treatment on high-temperature deformation behavior of as-cast TiZrAlV alloy

摘要:

为了研究置氢处理对45Ti-47Zr-5Al-3V合金高温变形行为及显微组织的影响规律，本文利用动态热模拟试验机，对置氢与未置氢的铸态合金在不同变形条件下进行热压缩，系统研究了材料的高温变形行为及其微观组织演化规律，并构建了本构方程及热加工图。加入适量的氢可以显著降低TiZrAlV合金的流变应力和变形激活能，计算得到未置氢合金热压缩变形激活能为339.7kJ/mol，而置氢后的激活能为286.5kJ/mol，适宜的加工参数为650-900℃，0.01-1s-1。OM和EBSD微观组织观察表明，置氢能细化铸态组织，增加β相含量，促进动态再结晶，从而显著降低了合金的流变抗力，扩大了热加工窗口，提高了热加工性能。

Abstract:

In order to study the influence of hydrogen on the high temperature deformation behavior and microstructure evolution of 45Ti-47Zr-5Al-3V alloy, a dynamic thermal simulation machine was used for the as-cast alloy with and without hydrogen under different deformation conditions. The flow stress and deformation activation energy of TiZrAlV alloy can be significantly reduced by adding proper amount of hydrogen. The activation energy of unhydrogenated and hydrogenated alloy is 339.7 kJ/mol and 286.5 kJ/mol. Meanwhile, the optimum thermal processing parameters are 700-900℃, 0.01-1s-1. The OM and EBSD microstructure observations show that adding hydrogen can refine the as-cast structure, increase the β-phase content and promote dynamic recrystallization, thus significantly reducing the flow resistance of the alloy, expanding the hot processing window and improving the thermal processing performance.