Microstructure evolution and property characteristics in hot-pressed Mo-W-Cu refractory functional alloys with varying tungsten content

Abstract

Mo-W-Cu refractory functional alloys (RFAs), combining property advantages of MoCu and WCu alloys, have great application potential in microelectronics, aerospace technology, and military equipment due to their excellent electrical and thermal conductivity, low coefficient of thermal expansion, and high-temperature properties. W content in the alloy is a key factor influencing these properties. However, there is a lack of systematic investigation on the microstructure and properties of hot pressing (HP) processed Mo-W-Cu RFAs with different W contents these days. In this study, Mo-W-20Cu alloys with varying W content of 0–50 wt% RFAs are prepared by mechanical activation (MA) followed by hot pressing. The effect of W content on the microstructure and properties of the alloy is investigated in detail. The results show that all Mo-W-Cu RFAs mainly consist of Mo phase, W phase, and Cu phase after adding W. The microstructure observation shows that the Cu powder particles undergo a plastic deformation during the HP processing, resulting in the closure of the pores and the good metallurgical bonding with Mo phase and W phase at a relatively low temperature. Transmission electron microscopy (TEM) determination indicates that the MoCu phase interface and that of WCu both possess a semi-coherent structure. The property measurements demonstrate that the electrical and thermal conductivity properties of Mo-W-Cu RFAs continuously increase with W content rising while the relative densities of all the alloys are over 94 %. This study can provide a valuable theoretical and technological guidance for the investigation on preparation, microstructure, and properties of high-performance RFAs.