Effects of Rare Earth Ce on the Brazing Performance of High Energy Mechanical Milling Cu-Based Alloy Powder

Abstract

CuSn and TiH2 powders were milled by high energy mechanical milling to prepare Cu-based alloy powder for brazing diamond, and a small amount of rare earth Ce was added to improve the brazing performance. The effects of Ce on the brazing performance were studied by investigating transverse rupture strength, microstructure of brazing layer, climbing height along the diamond, and wear characteristics of the diamonds. The results indicated that the addition of Ce could effectively improve the transverse rupture strength, the transverse rupture strength reached the maximum value 475 MPa when the Ce content was 0.75 wt %. Rare earth Ce could promote the refinement of Cu6Sn5 and CuTi2 grains in the brazing alloy, which effectively reduced the formation and propagation of cracks. The wettability of the Cu-based alloy was also improved by adding rare earth Ce, and the capillary force pulled the molten alloy up the diamonds and formed a hill-like structure around diamonds. The diamonds brazed with Cu-based alloy containing 0.75 wt % Ce mainly led to integrity, micro-fracture, fracture and rubdown during the grinding process; pull-out of diamonds did not happen easily owing to the presence of strong adhesion between the diamonds and Cu-based alloy.