摘要
目的解决TC21钛合金六角头螺栓冷镦成形困难的难题。方法利用置氢处理改善TC21钛合金的冷镦成形性能,利用电子万能材料试验机对未置氢和置氢TC21钛合金六角头螺栓进行冷镦成形,利用金相显微镜、X射线衍射仪、透射电子显微镜和显微维氏硬度计等设备对未置氢和置氢TC21钛合金冷镦六角头螺栓的显微组织和显微维氏硬度进行分析。结果在冷镦成形过程中,置氢TC21钛合金六角头螺栓未出现缺陷,而未置氢TC21钛合金六角头螺栓则出现了裂纹。未置氢和置氢TC21钛合金冷镦六角头螺栓的头部均呈现出“一字双岔状变形带”,在未置氢TC21钛合金冷镦六角头螺栓头部变形带的分岔处出现了裂纹。与未置氢TC21钛合金冷镦六角头螺栓相比,置氢TC21钛合金冷镦六角头螺栓的显微组织发生了显著变化。在置氢TC21钛合金冷镦六角头螺栓中,α相和β相的光学对比度与未置氢合金的相反,α相含量减少,β相含量增加,β相成为合金的主要相,并发现了较多的位错。置氢TC21钛合金冷镦六角头螺栓各区的显微维氏硬度均低于未置氢TC21钛合金冷镦六角头螺栓各区的显微维氏硬度。结论置氢处理有利于TC21钛合金六角头螺栓的冷镦成形。
The work aims to address the challenge of TC21 titanium alloy hexagonal bolts formed by cold heading.The cold heading performance of TC21 titanium alloy was enhanced by hydrogenation treatment.The nonhydrogenated and hydrogenated TC21 titanium alloy hexagonal bolts were subject to cold heading with an electronic universal material testing machine.The microstructure and microhardness of nonhydrogenated and hydrogenated TC21 titanium alloy hexagonal bolts were studied with a metallographic microscope,an X-ray diffractometer,a transmission electron microscope,and a microhardness tester.Hydro-genated TC21 titanium alloy hexagonal bolts exhibited no defects during the cold heading,whereas the nonhydrogenated TC21 titanium alloy hexagonal bolt experienced cracking during the cold heading.Both the nonhydrogenated and hydrogenated TC21 titanium alloy cold-headed hexagonal bolts exhibited a"bilateral forked deformation band"in their heads.Cracks appeared at the fork areas of the deformation band in the head of the nonhydrogenated TC21 titanium alloy cold-headed hexagonal bolt.Compared with the nonhydrogenated TC21 titanium alloy cold-headed hexagonal bolt,significant changes were observed in the microstructure of the hydrogenated TC21 titanium alloy cold-headed hexagonal bolt.In the hydrogenated TC21 titanium alloy cold-headed hexagonal bolt,the optical contrast betweenαphase andβphase was opposite to each other.The amount ofαphase decreased while the amount ofβphase increased,βphase became the dominant phase in the alloy,and many dislocations were observed.The microhardness in each region of the hydrogenated TC21 titanium alloy cold-headed hexagonal bolt was lower than that of the nonhydrogenated TC21 titanium alloy cold-headed hexagonal bolt in its respective regions.Hydrogenation treatment benefits the cold heading of TC21 titanium alloy hexagonal bolts.
作者
张小雪
宗胜杰
马志远
袁宝国
ZHANG Xiao-xue;ZONG Sheng-jie;MA Zhi-yuan;YUAN Bao-guo(School of Mechanical Engineering,Anhui Sanlian University,Hefei 230601,China;School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China)
出处
《精密成形工程》
北大核心
2023年第10期136-142,共7页
Journal of Netshape Forming Engineering
基金
国家自然科学基金(52275328,51875157)
安徽高校优秀拔尖人才培育资助项目(gxyq2021238)
安徽高校自然科学重点科研项目(2023AH051703)。
关键词
钛合金
六角头螺栓
冷镦
显微组织
显微维氏硬度
titanium alloy
hexagonal bolt
cold heading
microstructure
microhardness
