Influence of TiH2 on Interfacial Reaction Features Between Cubic Boron Nitride and Cu-Sn-Ti Active Filler Metals
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Cubic boron nitride (CBN) grains are brazed by Cu-Sn-Ti filler metal in vacuum at 1223 K. Wetting behaviors, reaction layer features, and elemental distribution characteristics have been systematically investigated through scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The results show that when the TiH2 content is 5 wt pct, virtually no sharp-edged, partially coated, and uncoated CBN grains can be observed, indicating that adequate wetting could be achieved. Moreover, a continuous reaction layer with uniform thickness (1.30 μm) consisting of TiN, TiB2, and TiB is obtained, which indicates that large numbers of TiN, TiB2, and TiB compounds could have been formed at the interface. However, when the TiH2 content exceeds 5 wt pct, the thickness of the reaction layer is no longer significantly expanding and excessive Ti present in the matrix will lower the volume percentage of Cu3Sn1 phase, which will reduce the bonding strength of the brazing samples. Wear tests indicate that the minimum weight loss also occurs at 5 wt pct TiH2.
The authors gratefully acknowledge the National Natural Science Foundation of China (Grant Nos. 51622401, 51628402, 51861130361, 51861145312, and 51850410522), Newton Advanced Fellowship by Royal Society (Grant No. RP12G0414), Research Fund for Central Universities (Grant No. N172502004), National Key Research and Development Program of China (Grant No. 2016YFB0300602), and Global Talents Recruitment Program endowed by the Chinese Government for their financial support. We also thank the State Key Laboratory of Solidification Processing, Northwestern Polytechnical University (Grant No. SKLSP201805).
- 5.H.M. Lin, Y.S. Liao, and C.C. Wei: J. Manuf. Sci. Produc., 2015, vol. 264, pp. 679–84.Google Scholar