MoB₂/MoB ceramic particulate reinforced W-1 wt % Ni matrix composites as potential plasma facing materials

This study reports on the synthesis and characterization of MoB₂/MoB ceramic particulate reinforced W-1 wt % Ni matrix (W1Ni) composites for their potential usage as plasma facing materials. A powder metallurgical route consisting of mechanical alloying (MA), cold pressing (CP), cold isostatic pressing (CIP) and pressureless sintering (PS) was applied for the production of MoB₂/MoB particulate reinforced W1Ni composites. Different percentages of MoB₂/MoB (x = 1, 2, 5 and 10 wt %) were incorporated into W1Ni pre-alloy. MA was performed in a planetary ball mill for different times as 24, 48 and 72 h. After compaction using CP and CIP, green bodies were pressureless sintered at 1400 °C for 1 h under Ar/H₂ gas flow. According to the results of XRD characterization, and lattice strain, crystallite size and particle size analyses performed on the powders, MA time was determined as 72 h with an average lattice strain of 2.37% and crystallite size of 7.40 nm. Sintered samples characterized in terms of compositional, microstructural, wear, density and microhardness properties exhibited that W1Ni-10 wt % MoB₂/MoB composite has the highest hardness value of ∼6.74 GPa and the lowest wear volume loss of 2.08 × 10^-4 mm³, as compared to those of other samples. Sintered samples exposed to 20 eV He⁺ ion irradiation with a flux of 1.102 × 10²¹ ions/(m²s), irradiation fluence of 1.32 × 10²⁴ ions/m² for 20 min had a degraded wave-shaped structure (wavy erosion layers) on their surfaces. However, W1Ni-2 wt % MoB₂/MoB composite showed relatively more resistant to ion irradiation attributed to its higher densification rate.