γ-TiAl表面双辉等离子W-Mo合金化对其氧化行为的影响  

Effect of W-Mo Alloying of Double Glow Plasma on γ-TiAl Surface on Oxidation Behavior

作　　者：张李波 魏东博[1] 张平则[1] 陈小虎[1] 丁丰[1] ZHANG Li-bo;WEI Dong-bo;ZHANG Ping-ze;CHEN Xiao-hu;DING Feng(Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China)

机构地区：[1]南京航空航天大学,南京211106

出　　处：《表面技术》2018年第4期17-23,共7页Surface Technology

基　　金：国家自然科学基金(51371097);江苏省基础研究计划(自然科学基金)-青年基金项目(BK20140819);航空科学基金项目(2016ZF52056);中央高校基本科研业务费专项资金资助(NS2015059)~~

摘　　要：目的研究W-Mo表面合金化对γ-TiAl合金抗高温氧化性能的影响。方法采用双层辉光等离子合金化技术在γ-TiAl合金表面进行W-Mo合金化,通过恒温氧化试验评价改性层的抗氧化性能,并通过扫描电子显微镜与X射线衍射仪对氧化膜表面及截面形貌和相组成进行分析。结果使用双层辉光等离子合金化技术可以在γ-TiAl表面制备出W-Mo改性层,改性层厚度为9μm,最外层为厚约6μm的W-Mo沉积层,而在沉积层与基体之间存在厚约3μm的扩散层。W-Mo改性层均匀、致密,基体与改性层之间没有裂纹、孔洞等明显缺陷,扩散层中的元素含量呈梯度分布。在750℃恒温氧化100 h后,γ-TiAl基体的氧化增重为5.306 mg/cm^2,W-Mo改性层的氧化增重为2.578 mg/cm^2,仅为γ-TiAl基体的48.6%。在氧化10、20、50 h后,改性层表面无明显变化,氧化膜层均匀、致密、无缺陷,几乎没有出现剥落现象;氧化100 h后,改性层中Mo与W的原子比由3:1降低到了1:2。结论通过双层辉光等离子合金化技术制备W-Mo改性层,能够改善γ-TiAl合金在750℃下的抗高温氧化性能。W-Mo改性层在经过氧化后所形成的氧化膜连续、致密,可以阻碍氧原子向基体内的扩散。但在氧化100 h后,Mo元素的蒸发会破坏氧化膜的完整性,使抗氧化性能有所降低。The work aims to study the effect of W-Mo surface alloying on the high temperature oxidation resistance of γ-TiAl alloy. W-Mo alloying on the surface of γ-TiAl alloy was prepared by double glow plasma surface alloying technology.The oxidation resistance of modified layers was evaluated by isothermal oxidation test. The surface, morphology of cross section and phase composition of oxidation film were anaylized by scanning electron microscope （SEM） and an X-ray diffractome- ter （XRD）. W-Mo modified layer could be prepared on the surface ofy-TiA1 by double glow plasma surface alloying technology. The modified layer was 9 μm and the outer layer was 6 μm W-Mo deposition layer. 3 μm diffusion layer was between the depo- sition layer and the substrate. The W-Mo modified layer was even and dense and the substrate and the modified later had no obvious defects like crack, hole, etc. The content of elements in diffusion layer was distributed in gradient. After isothermal oxidation of 100 h at 750℃, the oxidation mass gain of γ-TiA1 reached 5.306 mg/cm^2 and that of modified layer increased to 2.578 mg/cm^2. The mass gain of W-Mo modified layer was only 48.6% of that of γ-TiAl substrate. The modified layer was uniform, dense and free from defects and peeling after oxidation for 10 h, 20 h and 50 h. After oxidation for 100h, the atomic percentage of Mo and W in modified layer decreased to 1：2 from 3：1. The W-Mo modified layer prepared by double glow plasma surface alloying technology can improve the high-temperature oxidation resistance of γ-TiAl alloy at 750℃. The oxide film of W-Mo modified layer is continuous and tight after oxidation andcan prevent the diffusion of oxygen. But after oxidation of 100 h, the evaporation of Mo will destroy the integrity of the oxide film and decrease the oxidation resistance.

关 键 词：Γ-TIAL合金 表面合金化 W-Mo改性层 双层辉光等离子合金化技术 恒温氧化 氧化行为 

分 类 号：TG174.4[金属学及工艺—金属表面处理]