热处理工艺对V-5(Al-5Ti-1B) 氢分离合金显微组织、硬度和轧制性能的影响

Effect of heat treatment on microstructure, hardness and rollability of V-5 (Al-5Ti-1B) alloys for hydrogen separation

摘要:

在真空电弧炉中熔炼制备V-5(Al-5Ti-1B)合金（V-5ATB合金），采用光学显微镜、X射线衍射仪、硬度测试和轧制性能测试技术，研究固溶处理温度和时间对V-5ATB合金的显微组织、硬度和轧制性能的影响。研究结果表明：V-5ATB合金在800和900 ℃固溶处理，随着温度升高，TiB相逐渐溶入V基固溶体（Vss），晶粒随之长大。合金TiB第二相析出强化及细晶强化的效应减弱程度大于固溶强化效应的增加程度，导致合金硬度随温度升高而降低。而在1000 ℃固溶处理时，合金中TiB相几乎完全溶入Vss中，固溶强化效应占主导使合金硬度值出现回升。V-5ATB合金在900 ℃固溶处理随着时间延长，TiB相逐步溶入到Vss中，晶粒随之长大。合金第二相析出强化及细晶强化的效应减弱程度大于固溶强化效应的增加程度，导致合金固溶处理后的硬度随时间延长而降低。V-5ATB合金较适宜的固溶处理工艺参数为900 ℃/2 h。固溶处理态合金的轧制性能相比于铸态的提升了约24%。

关键词:V基合金;Al-5Ti-1B;氢分离;固溶处理;显微组织;硬度;轧制性能

Abstract:

V-5 (Al-5Ti-1B) alloys (V-5ATB) were prepared by in vacuum electric arc melter. The effects of solution treatment temperature and time on the microstructure, hardness and rollability of V-5ATB alloys were studied by optical microscope, X-ray diffractometer, hardness testing and rollability testing technology. The results showed that, when V-5ATB alloys were solution treated at 800 and 900 ℃, TiB phases gradually dissolved into V–based solid solution (Vss) and the grains grew with the increasing temperature. The strengthening effect of TiB second phase and fine grains of the alloys is weakened more than the increase of solid solution strengthening effect, resulting in the hardness decrease of the alloys with the increasing temperature. When the alloys were solution treated at 1000 ℃, the TiB phases in the alloys were almost completely dissolved into Vss, and the solid solution strengthening effect is dominant, resulting in the hardness increase of the alloys. When V-5ATB alloys were solution treated at 900 ℃, TiB phases gradually dissolves into Vss and the grains grew with time. The weakening degree of the strengthening effect of the second phase and fine grain of the alloys is greater than the increase degree of the solid solution strengthening effect, resulting in the hardness decrease of the alloys after solution treatment with the extension of time. The optimum solution treatment parameter of V-5ATB alloys is 900 ℃/2 h. The rollability of the solution treated V-5ATB alloys is improved by about 24% compared with those of the as-cast alloys.

Key words:V-based alloy; Al-5Ti-1B; Hydrogen separation; Solution treatment; Microstructure; Hardness; Rollability