An investigation on synthesis development of high hardened, high conductivity Cu-Zr and Cu-Zr-ZrB2 alloys through green compact laser sintering

Abstract

Cold pressed mechanically alloyed Cu-1Zr (wt%) and Cu-4.1Zr-1.1B (wt%) powders were sintered by laser irradiation. Laser employed was pulsed, millisecond Nd:YAG laser system. The influence of different sintering parameters on structural, mechanical, and physical properties of laser-sintered materials was investigated. Microstructural changes during laser sintering were studied using scanning electron microscopy and X-ray diffraction. High hardening of the Cu-Zr alloy is achieved by thermal treatment due to the influence of the developed rapidly solidified structure and precipitation of metastable CuZr. In ternary Cu-Zr-B alloy rapidly solidified structure, as well as the presence of ZrB2 particles and metastable CuZr phase, affected much higher degree of copper matrix hardening which, thanks to the ceramic particles, is retained at high temperatures. It was determined that the optimum combination of high density, microhardness, and electrical conductivity is reached using the following parameters: laser frequency 3 Hz, laser pulse duration 8 ms, pulse energy similar to 19 J, number of scans 3 (binary alloy), i.e., 4 (ternary alloy).