层状结构TiAl合金钎焊组织及性能

Brazing Microstructure and Properties of TiAl Alloy with Layered Structure

目的揭示层状结构Ti Al合金薄板采用钎料Ti-Zr-Cu-Ni时,在钎焊过程中的扩散行为,以及钎焊后的组织和力学性能。方法对焊缝及周边区域进行电子扫描(SEM)、能谱分析(EDS)、X射线衍射分析(XRD),明确钎焊过程中的扩散行为以及钎焊接头组织;对钎焊后的层状Ti Al合金进行剪切试验和纳米压痕试验,评价焊缝的力学性能。结果采用Ti-Zr-Cu-Ni钎箔钎焊Ti Al合金板材,Al元素为主要扩散元素,从母材向焊缝进行扩散,在Ti Al合金与钎料界面处生成Ti_3Al金属化合物,在焊缝处生成(Ti,Zr)_2(Cu,Ni)(s,s),Ti_2(Cu,Ni)(s,s),(Ti,Zr)_2Ni(s,s)和α-Ti。焊后接头的剪切强度为252 MPa,裂纹在母材处生成,穿过焊缝扩展到另一侧母材区域发生断裂,焊缝区硬度值高于母材,为12.8 GPa。结论选用Ti-Zr-Cu-Ni钎料在930℃下进行钎焊,能够获得质量良好的接头。

The paper aims to reveal the dispersal behavior of Ti-Zr-Cu-Ni solder with TiAl alloy sheet in brazing and its microstructure and mechanical properties after brazing. Techniques of scanning electron microscopy（SEM）, energy dispersive spectrometer（EDS）, X-ray diffraction（XRD） were employed to analyze dispersal behavior and microstructure of soldered joint. Shear test and nanoindentation test were carried out on lamelleted TiAl alloy after brazing to evaluate mechanical property of welds. With Ti-Zr-Cu-Ni as solder of TiAl alloy sheet, the Al element was the main diffusion element diffusing from the weld to the base material. Ti3Al metal compound was formed at the interface between TiAl alloy and brazing filler metal. There were（Ti, Zr）2（Cu,Ni）（s, s）, Ti2（Cu, Ni）（s,s）,（Ti, Zr）2 Ni（s, s） and α-Ti at the weld. The shear strength of the welded joint was 252 MPa. The crack was generated at the base material and was spread through the weld to the other side of the base material area. The hardness of the weld zone was higher than that of the base metal, which was 12.8 GPa. The use of Ti-Zr-Cu-Ni solder at 930 ℃for brazing can obtain joints of good quality.