Ag-Cu-Ti钎焊金刚石的界面结构及热应力分析

Interface Microstructure and Thermal Stress of Diamond Brazing with Ag-Cu-Ti Filler

采用Ag-Cu-Ti钎料对金刚石进行真空钎焊实验,实现了金刚石与钢基体的高强度连接。采用SEM对金刚石与钎料界面、金刚石表面碳化物形貌进行观察分析,采用EDS分析金刚石表面碳化物的成分,利用XRD对焊后金刚石磨料的进行物相分析,采用Raman光谱对焊后的金刚石是否石墨化、残余应力进行分析。结果表明:Ag-Cu-Ti钎料中的Ti元素在界面处发生偏析,并在金刚石表面生成尺寸小于1μm的块状TiC。金刚石在焊接过程的高温下没有发生石墨化。金刚石中的最大拉应力位于磨粒顶部,为60 MPa,最大压应力在底部,为120 MPa。最后在界面上形成了金刚石/TiC/钎料/钢基体的梯度结合层。

A firm joint between steel base and diamond was realized by using Ag-Cu-Ti brazing diamond in vacuum. The interface between diamond and filler and carbide formed on the diamond surface was analyzed by using SEM, EDS, XRD and Raman Spectroscope. Results showed that carbide layer was formed as a result of the reaction between Ti and diamond, and discontinuous-lump-like TiC carbide with less than 1 ~tm on the surface of diamond appeared. There was almost no heat damage in the brazed diamond. The maximal tensile stress in the diamond located at the top reached 60 MPa, while the maximal compressive stress located at the bottom was 120 MPa. As a result, the metallurgical bonding was obtained between filler metal and diamond through the forming the serial of diamond-TiC-filler layer.