Efficient Sintering of Mo Matrix Composites—A Study of Temperature Dependences and the Use of the Sinter Additive Ni

Abstract

Mo matrix composites (MMC) with Mo-9Si-8B inclusions were fabricated by pressure-less sintering (PLS) and spark plasma sintering (SPS) techniques at temperatures between 1200–1500 °C using 1 wt.% Ni sinter additive. The positive impact of the addition Ni addition on the sinterability and formation of a continuous Mo matrix of MMC with randomly distributed Mo3Si and Mo5SiB2 inclusions was determined. The Ni addition increased the shrinkage of MMC during PLS by almost a third. The continuous Mo matrix of MMC and a relative density of more than 98% was obtained after SPS at 1400–1500 °C. The composite with the maximum relative density of 98% showed a Vickers hardness of 482 ± 9 (HV20). The potential of using Ni-activated PLS and SPS to produce high-density MMC is shown.

Keywords

• Mo alloys
• metal–matrix composites
• pressure-less sintering
• spark plasma sintering
• structure