激光熔覆原位自生Ti-Al-B功能涂层的结构特征及其高温抗氧化性能  

Microstructure and High-Temperature Oxidation Resistance of In-Situ Ti-Al-B Functional Coatings by Laser Cladding

作　　者：刘洪喜[1,2] 陈菊 杨琛 刘亚霞 王悦怡 郝轩弘[1] LIU Hongxi;CHEN Ju;YANG Chen;LIU Yaxia;WANG Yueyi;HAO Xuanhong(Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;Editorial Office of Journal of Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]昆明理工大学学报编辑部,云南昆明650500

出　　处：《昆明理工大学学报（自然科学版）》2024年第3期42-54,共13页Journal of Kunming University of Science and Technology(Natural Science)

基　　金：国家自然科学基金项目(61963021);云南省基础研究计划重点基金项目(202101AS070110).

摘　　要：为改善钛合金固有高温抗氧化性较差而影响其在极端环境下长寿命服役的问题,采用激光熔覆原位自生技术在TC4钛合金表面制备了Ti-Al-B功能涂层.通过XRD、OM、SEM、XPS、显微硬度计、管式电阻炉分别表征了涂层的物相组成、金相组织、微观形貌、显微硬度和在800℃下循环氧化120 h后的抗氧化性能.结果表明,涂层与基材形成了良好的冶金结合,涂层由α-Ti、Ti_(3)Al、TiB、Al_(2)O_(3)及少量Ti的氧化物组成.涂层中的Ti主要以Ti和Ti_(3)Al形式存在,Al主要以Ti_(3)Al和Al_(2)O_(3)形式存在.涂层最高显微硬度达到1177.5 HV_(0.2),是基材的3.27倍.涂层在800℃下循环氧化120 h后的抗氧化性能较TC4钛合金基材提高了10~15倍.涂层高温抗氧化性能得以改善的原因主要归功于B对组织的晶粒细化和涂层表面连续致密氧化膜对空气中氧向涂层内扩散的阻碍作用.激光熔覆原位自生Ti-Al-B功能涂层能显著改善钛合金的高温抗氧化性能.In order to improve the inherent poor high-temperature oxidation resistance and extend the service life of titanium alloy in extreme environments,Ti-Al-B functional coating was prepared on TC4 titanium alloy surface by in-situ laser cladding technology.The phase composition,metallographic structure,microstructure,microhardness,and high-temperature oxidation resistance of the coating after 120 hours at 800℃cyclic oxidation condition were characterized by XRD,OM,SEM,XPS,microhardness tester,and tubular resistance furnace,respectively.The results showed that the coating formed a good metallurgical bond with the substrate,and the coating was composed ofα-Ti,Ti_(3)Al,TiB,Al_(2)O_(3),and a small amount of Ti oxide.Ti in the coating mainly exists in the forms of Ti and Ti_(3)Al,while Al mainly exists in the forms of Ti_(3)Al and Al_(2)O_(3).The maximum microhardness of the coating reaches 1177.5 HV_(0.2),which is 3.27 times that of the substrate.The oxidation resistance of the coating after 120 hours at 800℃cyclic oxidation condition is 10-15 times higher than that of TC4 titanium alloy substrate.The main reason for the improvement of the high-temperature oxidation resistance of the coating is attributed to the grain refinement of B and the hindering effect of the continuous dense oxide film on the surface of the coating on the diffusion of oxygen from the air into the coating.Laser cladding in-situ Ti-Al-B functional coatings can significantly improve the high-temperature oxidation resistance of titanium alloys.

关 键 词：激光熔覆原位自生 功能涂层 钛合金 微观组织 高温抗氧化性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TG665[金属学及工艺—金属学]