New utilization approach of microwave thermal energy: Preparation of metallic matrix diamond tool bit by microwave hot-press sintering

Abstract

Sintering is a critical process for the preparation of metallic matrix diamond tools. The purpose of this work aims to propose a novel microwave hot-press sintering (MHPS) method for the improvement of mechanical properties for Fe-Cu-W-Sn matrix diamond tools. The samples were prepared by MHPS and conventional hot-press sintering (CHPS), respectively. The microstructures of samples were characterized using XRD, EMPA, and SEM tests. The mechanical properties of samples, such as relative density, hardness, bending strength, and impact toughness were also investigated. Experimental results show that the samples by MHPS method has obvious advantages with shorter sintering time, lower sintering temperature, more uniform element diffusion, and better holding situation of diamond abrasives in the alloyed matrix. The optimal mechanical properties of samples sintered by MHPS at 850 °C, to be specific, including relative density, hardness and flexural strength reach 97.8%, 99.2 HRB and 986 MPa, respectively. The possible mechanism of MHPS is discussed. This work can provide a reference for microwave sintering of metallic matrix diamond tools.