固溶处理工艺对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 Solution Treatment on Microstructure,Hardness and Rollability of V-5(Al-5Ti-1B)Alloys for Hydrogen Separation

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%。

V-5(Al-5Ti-1B) alloys(V-5ATB) were prepared by melting 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 show that when V-5ATB alloys are solution treated at 800and 900 ℃, TiB phases gradually dissolve into V-based solid solution(Vss) and the grains grow with the increasing temperature. The weakening degree of the strengthening effect of TiB second phase and fine grains of the alloys is greater than the increase degree of the solid solution strengthening effect, resulting in the hardness of the alloys decrease with the increasing temperature. When the alloys are solution treated at 1000 ℃, the TiB phases in the alloys almost completely dissolve into Vss, and the solid solution strengthening effect is dominant, resulting in the hardness of the alloys increase. When V-5ATB alloys are solution treated at 900 ℃, TiB phases gradually dissolve into Vss and the grains grow with the extension of 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 of the alloys after solution treatment decrease 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 alloy is improved by about 24% compared with those of the as-cast alloys.