TiAlNb9合金表面B-Y改性硅化物渗层的组织及热冲击性能  

Microstructure and thermal impact property of B-Y doped silicon compound coating on TiAlNb9 alloy surface

作　　者：王存喜 梁国栋 田兴达 李涌泉 Wang Cunxi;Liang Guodong;Tian Xingda;Li Yongquan(School of Materials Science and Engineering,North Minzu University,Yinchuan Ningxia 750021,China;School of Electrical and Mechanical Engineering,North Minzu University,Yinchuan Ningxia 750021,China)

机构地区：[1]北方民族大学材料科学与工程学院,宁夏银川750021 [2]北方民族大学机电工程学院,宁夏银川750021

出　　处：《金属热处理》2023年第6期142-146,共5页Heat Treatment of Metals

基　　金：国家自然科学基金(51961003,52161009);宁夏自然科学基金(2022AAC03224);服务宁夏九大产业专项(FWNX42)。

摘　　要：采用15Si-4B-8NaF-2Y_(2)O_(3)-71Al_(2)O_(3)(质量分数,%)渗剂包埋渗法在TiAlNb9合金表面制备了B-Y改性的硅化物渗层,并通过扫描电镜、X射线衍射仪及电子探针分析了渗层的结构及相组成,对比研究了Si-B-Y共渗层制备前后TiAlNb9合金热冲击性能的变化。结果表明,经1050℃保温6 h所制备的Si-B-Y共渗层具有组织均匀致密的复合结构,厚约14μm,其外层主要为TiB_(2)相和(Ti,Nb)Si_(2)相,中间层为(Ti,Nb)_(5)Si_(3)相,内层为TiAl_(2)相和少量TiB相。在1000℃热冲击下,TiAlNb9基体裂纹一旦产生,将会持续扩展,中间会有树枝状裂纹产生,在热冲击47次后出现贯穿性裂纹;而Si-B-Y共渗层裂纹萌生时间较长,裂纹的萌生具有多发和弥散性,随着热冲击次数的增加,最终多处细小裂纹汇合一处,在热冲击59次后贯穿基体,但裂纹未在膜基界面处发生横向扩展,且整体渗层未出现脱落的现象,表明Si-B-Y共渗层可以在一定程度上提高TiAlNb9合金的抗热冲击性能。B-Y doped silicon compound coating was prepared on surface of TiAlNb9 alloy by pack cementation process with 15Si-4B-8NaF-2Y_(2)O_(3)-71Al_(2)O_(3)(mass fraction,%),the structure and phase composition of the co-deposition coating were analyzed by means of scanning electron microscopy,X-ray difractometry and electron probe,and the thermal impact properties of Si-B-Y co-deposition coating and TiAlNb9 substrate were compared.The results show that the Si-B-Y co-deposition coating prepared by holding at 1050℃for 6 h has an uniform and dense composite structure with a thickness of about 14μm.The outer layer consists of TiB_(2)and(Ti,Nb)Siz phases,the middle layer consists of(Ti,Nb)_(5)Si_(3)phase,and the inner layer consists of TiAl_(2)and small amounts of TiB phases.Under the thermal impact at 1000℃,the substrate cracks in the TiAlNb9 alloy continue to grow,and there are bifurcated cracks in the middle,the penetrating cracks appear after 47 times of thermal impact.However,the Si-B-Y co-deposition coating has a long crack initiation time,the initiation of cracks is frequent and dispersive,and with the increase of the number of thermal impact,several small cracks finally merge into one place and penetrate through the substrate after 59 times of thermal impact,but the cracks do not extend horizontally at the interface of the film base,and the whole deposition layer does not fall off,indicating that Si-B-Y co-deposition coating can improve the thermal impact property of the TiAlNb9 alloy to a certain extent.

关 键 词：TiAlNb9合金 包埋渗法 硅-硼-钇共渗层 热冲击性能 

分 类 号：TG166.5[金属学及工艺—热处理]