The effect of (ZrB2-SiC) addition on microstructure and mechanical properties of NbMo-matrix composites fabricated by hot-pressing

Abstract The effects of (0–60%) vol% (70 vol% ZrB2 + 30 vol% SiC) additions on microstructure and properties of NbMo substrate fabricated by hot-pressing were studied at room temperature. Types of formed phase were decided by the amount of ZrB2 and SiC additives. The effective eutectic phase was observed in 15 vol% (70 vol% ZrB2 + 30 vol% SiC)-NbMo, which was attributed to the addition of SiC. 30 vol% (70 vol% ZrB2 + 30 vol% SiC)-NbMo had the highest relative density of 98.69%. Compared with x ZrB2-NbMo composites, the addition of SiC could further improve the hardness of NbMoss in x (70% ZrB2 + 30% SiC)-NbMo when the value of x was same, and NbMoss in 60 vol% (70 vol% ZrB2 + 30 vol% SiC)-NbMo had the highest hardness of 6.82 GPa. Only the 15 vol% (70 vol% ZrB2 + 30 vol% SiC) addition could improve the compressive strength of NbMo matrix. The reasons for the low strength of 30, 45, 60 vol% (70% ZrB2 + 30% SiC)-NbMo were the lack of ductile phase and the large amount of hard phase production.