| LIU Sixing,ZHANG Zechen,LIU Mingmiao,PENG Kang,HU Hongyu,WU Duoli.Interface Characteristics and Thermal Damage Mechanism of Vacuum and Argon Brazed Diamond by Ni-Cr-B-Si Filler Alloy[J],54(3):202-209, 219 |
| Interface Characteristics and Thermal Damage Mechanism of Vacuum and Argon Brazed Diamond by Ni-Cr-B-Si Filler Alloy |
| Received:January 09, 2024 Revised:March 24, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.03.018 |
| KeyWord:diamond brazing argon bonding interface hard point phase thermal damage |
| Author | Institution |
| LIU Sixing |
School of Mechanical Engineering, Yangzhou University, Jiangsu Yangzhou , China |
| ZHANG Zechen |
School of Mechanical Engineering, Yangzhou University, Jiangsu Yangzhou , China |
| LIU Mingmiao |
School of Mechanical Engineering, Yangzhou University, Jiangsu Yangzhou , China |
| PENG Kang |
School of Mechanical Engineering, Yangzhou University, Jiangsu Yangzhou , China |
| HU Hongyu |
School of Mechanical Engineering, Yangzhou University, Jiangsu Yangzhou , China |
| WU Duoli |
School of Mechanical Engineering, Yangzhou University, Jiangsu Yangzhou , China |
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| Abstract: |
| During the high-temperature brazing process, the interaction between the diamond interface, filler alloy and substrate through diffusion and chemical reaction results in high bonding of the abrasive grains, which fundamentally improves the bonding strength. Therefore, the diamond brazing technique with high grits holding strength compared with traditional electroplated and resin binder process can effectively improve the grinding efficiency and service life. However, it is found that diamond brazing with Ni-Cr filler alloy has the following disadvantages. The residual thermal stress around diamond interface may occur during high temperature brazing process. In case of inappropriate brazing temperature, micro cracks are prone to occur at the brazing diamond interface. The hardness of the brazing surface increases while the plasticity decreases, which will make the residual stress on the diamond interface larger. The catalyst element (Ni) of diamond synthesis, which may accelerate the graphitization of diamond during high temperature brazing, leading to a certain degree of thermal damage. Most previous researches on higher temperature brazing flaws have focused on heating temperature, filler alloy composition and coating, but no studies on atmosphere have been intensively conducted. Therefore, this study explores and reveals the interfacial properties and thermal damage of Ni-Cr-B-Si alloy brazing material for high temperature brazing of diamond in vacuum and argon atmospheres through brazing experiments and characterization analysis. In this study, active Ni-Cr-B-Si filler alloy brazing material is used to braze diamond/304 stainless steel in vacuum and argon atmospheres, respectively. A scanning electron microscopy (SEM) is used to observe the interfacial micromorphology of brazed diamond/filler alloy and the joint surface of the filler alloy/steel matrix. An energy dispersive spectroscopy (EDS) is applied to analyze the elemental diffusion distribution at the interface. An X-ray diffraction (XRD) is employed to determine the phase composition of the interfacial products, and a laser confocal Raman spectroscopy is selected to analyze the residual stress and thermal damage of brazed diamond. The results show that, the tensile shear strength of the brazed filler alloy/steel matrix joint in vacuum is 133.05 MPa, and that of the brazed joint in argon atmosphere is 125.10 MPa. And the brittle fracture is the main fracture of the brazed joint in both atmospheres. The interfacial product of diamond after brazing in the argon atmosphere is characterized by a striated structure, and the diamond bonding interface does not produce cracks, and no hard point phases are generated in the interface structure. The surface residual stress of brazed diamond in the argon atmosphere (0.034 GPa) is less than that of diamond after brazing in vacuum (0.648 GPa). The relative intensities of the Raman peaks of brazed diamond in vacuum and argon atmospheres are 65% and 27% lower than that of original single crystal diamond, respectively. The research of brazing diamond in the argon atmosphere shows that the uniformity of the brazing diamond interface is improved, the hard point phase on the surface of molten brazing filler metal is effectively controlled, which is beneficial to improving the bonding strength of diamond abrasive particles and alleviating the degree of thermal damage of diamond. |
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