基于Ag-Cu-Ti钎料的超高频感应连续钎焊金刚石界面结构及残余应力

Interfacial Microstructure and Residual Stress of Continuously Brazed Diamond with Ag-Cu-Ti Alloy Using Ultra-high Frequency Induction

采用Ag-Cu-Ti合金钎料,在不同的超高频感应连续钎焊工艺条件下实现了金刚石磨粒与大尺寸钢基体的连接。借助扫描电镜(SEM)对钎焊后的金刚石界面微观结构进行观察,采用Raman光谱对钎焊后金刚石的残余应力状态进行了测试分析。结果显示,超高频感应连续钎焊金刚石表面Ti C晶体的生成处于非平衡态的过程。随着扫描速度的变化,Ti C晶体呈现球状和岛状,偏离了理想的正八面体形态。钎料层内部出现富Cu枝晶组织,而在45#钢基体表层形成了马氏体组织。钎焊后的金刚石磨粒顶部受到残余压应力,最大值为500 MPa,磨粒底部受到残余拉应力,最大值为150 MPa,这种分布趋势与传统真空炉中钎焊方法获得的残余应力分布刚好相反。

Monocrystalline diamond grains and Ag-Cu-Ti filler alloy were jointed by continuous brazing using ultra-high frequency induction. The interfacial microstructure of the brazed diamond was observed by scanning electron microscopy（SEM） and its residual stress was investigated by Raman spectroscope. The results reveal the formation of Ti C crystal is in non-equilibrium state during continuous brazing of ultra-high frequency induction. The formed Ti C takes on granular and island-like structure, far away from the equilibrium state. A little Cu-riched dendrite is observed in the filler alloy, and martensite is formed near the surface of steel substrate. The maximum compressive stress in the brazed diamond is 500 MPa at the top, while the maximum tensile stress is 150 MPa at the bottom. This result is opposite to the residual stress distribution obtained by furnace brazing.