γ-TiAl金属间化合物合金表面激光熔覆TiC-Ti-Al涂层研究

Investigations of Laser Cladding TiC-Ti-Al Coatings on γ-TiAl Intermetallic Alloy

在TiAl合金表面预置TiC-Ti-Al粉末层,通过激光熔覆处理制得了以TiC为增强相,以TiAl及少量Ti3Al金属间化合物为基体的复合材料涂层。采用光学显微镜和扫描电子显微镜(SEM)观察了熔覆层的显微组织形貌,用X射线衍射仪(XRD)和能谱分析仪(EDS)进行了熔覆层的物相分析,并分别测试了激光处理前后基材和熔覆层显微硬度的变化。研究了激光扫描速度对熔覆层的显微组织和显微硬度的影响。结果表明:随着激光扫描速度的增加,增强相TiC颗粒形貌由树枝状向短棒状和颗粒状转变,并且均匀地弥散分布在熔覆层内,起到细晶强化和弥散强化的作用。同时,随着激光扫描速度的增加,熔覆层显微硬度有所提高,但厚度有所降低。

TiC-Ti-Al alloy powders were prepared on the surface of Ti-Al alloy. TiC reinforced TiAl matrix composite coatings is synthesized by laser cladding. The microstructure were observed by optical microscope （OM） and scanning electron microscopy （SEM） X-ray diffraction （XRD） and X-ray energy dispersive spectroscopy （EDS） were employed to analysis the phases composition of coating The changes of micro-hardness before and after laser processing were tested respectively. The results revealed that with the increase of laser scan-rate, the morphology of reinforced TiC homogeneously dispersed in TiAl matrix was changed into short-bar and particle shape from dendritic TiC. Meanwhile, the micro-hardness also increases but the thickness of the coating decreases.