气流磨处理钨粉的研究

在1143～1213 K、120～1500 s参数范围内以Ag-Cu-Ti箔为钎料对TiAl合金与42CrMo钢进行了真空钎焊试验.采用光学显微镜、扫描电镜、元素面扫描和能谱分析等方法对界面组织进行了分析,测量了界面反应层厚度.分析了界面反应层的形成过程及受控因素,计算了反应层成长的动力学参数.结果表明,接头界面反应层包括靠近TiAl合金的AlCuTi+Ti3Al层、AlCu2Ti层以及靠近42CrMo钢的TiC层,其成长活化能分别为324.97、207.97、338.03 kJ/mol.TiAl合金与钎科的界面反应层受控于液态钎料中的Cu元素,成长较快:42CrMo钢与钎料间的TiC层受控于固态钢中C元素,成长较慢.脆性反应层AlCuTi+Ti3Al层厚度为3.3μm时接头强度最高,脆性层厚度继续增大,接头强度显著下降.

Study on Jet Milling Processing of Tungsten Powder

Vacuum brazing of TiAl alloy and 42CrMo steel using Ag-Cu-Ti foil as filler metal was carried out in the parameter ranges of 1143 ~1213 K, and 120~1500 s. Microstructure and reaction phases were analyzed using optical microscope, scanning electron microscopy (SEM), and element distribution scanning, and the thickness of the reaction layer was measured. The formation of reaction phases and control factors were discussed and kinetics parameters were also calculated. Results show that there are three reaction layers at the interfaces, namely, AlCuTi+Ti3Al layer adjacent to the TiAl base metal, AlCu2Ti layer and the TiC layer adjacent to the 42CrMo steel. The activation energy of the reaction layers depicted above is 324.97, 207.97, 338.03 kJ/mol, respectively. Growth of the reaction layer adjacent to TiAl is controlled by the copper diffusion in the liquid braze, which shows faster character; TiC layer adjacent to the 42CrMo steel is controlled by the carbon diffusion in the solid steel, which shows slower growth. When the thickness of the brittle reaction layer of AlCuTi+Ti3Al is 3.3 mm, the joint strength reaches its highest value, and then the strength decreases quickly with the growth of the brittle reaction layer.