高强韧Ti55531钛合金表层梯度组织和硬度研究  

Study on surface gradient microstructure and microhardness of high-strength Ti55531 titanium alloy

作　　者：杨彪 姚利科 崔科 刘孝辰 李想 万明攀[1,2] Yang Biao;Yao Like;Cui Ke;Liu Xiaochen;Li Xiang;Wan Mingpan(School of Materials Science and Metallurgy,Guizhou University,Guiyang 550025,China;Key Laboratory of Guizhou Material Structure and Strength,Guiyang 550025,China)

机构地区：[1]贵州大学材料与冶金学院,贵州贵阳550025 [2]贵州省材料结构与强度重点实验室,贵州贵阳550025

出　　处：《轻金属》2024年第1期50-54,62,共6页Light Metals

基　　金：贵州大学大学生创新创业训练计划项目(贵大省创字(2021)031);中央引导地方科技专项(黔科中引地(2019)4011)。

摘　　要：对Ti55531钛合金采用高频感应加热1.8、1.9和2.0 s后进行水冷,然后分别在520、570和620℃进行6 h的时效处理,再利用光学显微镜(OM)、扫描电子显微镜(SEM)和显微硬度计(HV)对显微组织和硬度进行研究。结果表明:Ti55531钛合金经感应加热淬火后的显微组织呈梯度分布,试样表层组织以亚稳β相为主,而心部组织为双态组织,并且随着感应加热时间的增加梯度层深度也随之增加。时效处理过程中从表层亚稳β相中析出α+β相的片层组织,并且心部组织由片层组织和半等轴α相构成,呈现组织梯度。Ti55531钛合金经感应加热后,显微硬度从表层至心部基本保持不变且低于原始状态;但时效处理后,横截面的显微硬度从表层向心部逐渐递减,呈梯度分布,且整体硬度随着时效温度的升高而降低。Ti55531 titanium alloys were heated by high-frequency induction heating for 1.8 s,1.9 s and 2.0 s before water cooling,then the aging treatment was carried out at 520℃,570℃and 620℃for 6 h,respectively.The microstructure and microhardness of the Ti55531 titanium alloy were investigated through optical microscopy(OM),scanning electron microscopy(SEM)and microhardness tester(HV).The results show that the microstructure of Ti55531 titanium alloy after induction heating and quenching exhibits characteristics of gradient microstructure.The surface microstructure of the sample mainly consists of metastableβphase,while the center microstucture is composed of bimodal microstructure.And with the increase of induction heating time,the gradient layer depth of the alloy also increases.During the aging process,the lamellar microstructure ofα+βphase is precipitated from the surface metastableβphase,and the center microstructure is composed of lamellar microstructure and semi-equiaxedαphase,showing microstructural gradient.After the induction heating of Ti55531 alloy,the microhardness remains basically unchanged from the surface to the center,and lower than the original state.However,the cross section microhardness gradually decreases from surface layer to center after the aging treatment,showing a gradient distribution,and the overall hardness gradually decreases along with the increase of aging temperature.

关 键 词：Ti55531合金 感应加热 梯度组织 显微硬度 

分 类 号：TF823[冶金工程—有色金属冶金]