Nb掺杂对Ti-Al合金化层抗高温氧化性能的影响  

Effect of Nb Doping on High Temperature Oxidation Resistance of Ti-Al Alloyed Coatings

作　　者：戴景杰[1,2] 张丰云[2] 王阿敏[2] 陈传忠[1] 翁飞[1] 

机构地区：[1]山东大学材料液固结构演变与加工教育部重点实验室.济南250061 [2]青岛滨海学院机电工程学院,山东青岛266555

出　　处：《材料工程》2017年第2期24-31,共8页Journal of Materials Engineering

基　　金：山东省2016年重点研发计划项目(2016GGX102018)

摘　　要：为提高钛合金TC4的抗高温氧化性能,采用激光表面合金化技术在钛合金表面制备不同Nb掺杂量的Ti-Al合金化层。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)、箱式电阻炉等对合金化层的组织结构和高温氧化行为进行分析测试。结果表明,合金化层主要组成物相为TiAl以及少量的Ti_3Al相。Nb主要以置换溶质原子的形式固溶于合金化层中。合金化层组织均匀,与基体呈典型的冶金结合,在不含Nb的Ti-Al合金化层中发现大量的表层裂纹及少量的贯穿性裂纹,而在Nb掺杂的合金化层中未发现明显的宏观裂纹。合金化层在800℃保温1000h的氧化增重显著低于基体,表现出优异的抗高温氧化性能。相比而言,随着Al含量和Nb掺杂量的提高,合金化层的抗高温氧化能力也随之提高。Nb掺杂提高Ti-Al合金化层抗高温氧化性能的作用机理包括减少TiO_2中的空位缺陷、细化氧化物颗粒及促进Al_2O_3的形成。Ti-Al alloyed coatings with different Nb doping contents were fabricated on TC4 titanium alloy by laser surface alloying to improve high temperature oxidation resistance of the alloy.Structures and high temperature oxidation behaviors of the alloyed coatings were analyzed and tested by Xray diffraction（XRD）,scanning electron microscope（SEM）,energy dispersive spectrometer（EDS）and box-type resistance furnace.The results show that the alloyed coatings consist of TiAl and Ti3 Al,and no niobium compound are formed in Ti-Al-Nb alloyed coatings.The alloyed coatings are uniform and exhibit excellent metallurgical bonding with the substrates.A large amount of surface cracks and a few penetrating cracks are formed in Ti-Al alloyed coating without Nb doping,while no obvious cracks are formed in Ti-Al alloyed coating with Nb doping.The oxidation mass gains of all the alloyed coatings were significantly lower than those of the substrate.The alloyed coatings with Nb doping exhibit more excellent high temperature oxidation resistance due to the beneficial machanism of Nb doping.The mechanism of Nb doping on improving high temperature oxidation resistance of Ti-Al alloyed coatings includes reducing the defect concentration of TiO_2,refining oxide grains and promoting the formation of Al_2O_3.

关 键 词：钛合金 Ti-Al合金化层 Nb掺杂 抗高温氧化性能 

分 类 号：TG178[金属学及工艺—金属表面处理]