TiAl合金表面激光重熔纳米陶瓷涂层  

Laser remelting of nanostructured ceramic coatings on TiAl alloy

作　　者：田宗军[1,2] 王东生[2] 沈理达[2] 刘志东[1,2] 黄因慧[1,2] 

机构地区：[1]南京航空航天大学江苏省精密与微细制造技术重点实验室,江苏南京210016 [2]南京航空航天大学机电学院,江苏南京210016

出　　处：《材料热处理学报》2010年第2期128-132,共5页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金资助项目(59975046);江苏省自然科学基金重点项目(BK2004005)

摘　　要：采用等离子喷涂和激光重熔复合工艺在TiA l合金表面制备了纳米A l2O3-13wt%TiO2复合陶瓷涂层。为了使重熔后的陶瓷涂层保留一定的纳米结构组织,采用相对较低的激光功率和能量密度进行重熔。用扫描电镜(SEM)和X射线衍射仪(XRD)分析了涂层形貌、微观结构和相组成。结果表明,等离子喷涂纳米陶瓷涂层由纳米颗粒完全熔化区和部分熔化区两部分组成,具有等离子喷涂态的典型层状结构;由于受到激光功率、能量密度、陶瓷材料热物性参数和涂层厚度等因素的综合影响,重熔后陶瓷涂层出现了明显的分层结构特征;依据组织形态的不同,可将其大致分为:重熔区、烧结区和残余等离子喷涂区。重熔区由致密细小的等轴晶组成,并且保留了部分来源于原等离子喷涂部分熔化区的残留纳米粒子。由于等离子喷涂过程中涂层沉积时的快速凝固作用,涂层以亚稳相-γA l2O3为主,经过激光重熔处理后,-γA l2O3又重新转变为稳定相-αA l2O3。Nanostructured Al2O3-13wt%TiO2 composite ceramic coatings were prepared by plasma spraying and laser remelting on TiAl alloy surface.To retain nanopartilces in the plasma-sprayed nanostructured ceramic coating after laser remelting,a lower laser power and energy density were used.The morphology,microstructure and phases of the coating were investigated by means of X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The results show that the plasma-sprayed nanostructured ceramic coating with a lamellar-like structure as conventional coating consists of fully melted region and partially melted region. The laser remelted coating exhibits obvious layer-like characteristics due to influence of laser power,energy density,thermophysical parameters of ceramics and coating thickness.According to the microstructural morphology,the remelted ceramic coating can be divided into the remelted zone（with fine equiaxed grains）,the sintered zone and remained plasma-sprayed zone.Due to the rapid heating and cooling for laser remelting,some remained nanoparticles are observed in the remelted zone. θ-Al2O3 phase and partially α-Al2O3 phase are transformed into metastable phase of γ-Al2O3 after plasma spraying.While the metastable γ-Al2O3 phase in the remelted zone is re-transformed into stable phase of α-Al2O3 again after laser remelting.

关 键 词：激光重熔 等离子喷涂 纳米陶瓷涂层 微观组织 

分 类 号：TG156.99[金属学及工艺—热处理]