The effect of ball to powder ratio on the processing of a novel Mo-Cu-Al2O3 composite

In the present article a 45Mo-45Cu-10Al2O3 (wt%) nano-composite was produced by mechanical alloying, shaped cold pressing then hot at 950 °C. Our aim to investigate effect of different ball powder ratio (BPR) on particle size and shape, as well material composition. Investigations were done with XRD, SEM for pressed specimens Brinell hardness measurement. Lower BPR resulted in nano-sized crystallites powder, homogenous phase distribution higher even smaller crystallite sizes, but ZrO2 contamination from milling equipment. The two separate fractions metallic phases separated size, strain lattice parameter. After pressing, lower powders developed homogeneous, evenly distributed microstructure. Cu recrystallized during still remained nanocrystalline, Mo α-Al2O3 decreased more due deformation case Mo, values indicates that recovery had also happened. heating eliminated crystal defects highly strained areas subsequent cooling evened out stresses respective phases. inner grain structure revealed etching, showing particles congregated only boundaries, penetrated grains. combined BSE images reveal is main matrix particles. results indicate induced Particle Stimulated Nucleation (PSN) explaining its moderate increase. samples ceramic (ZrO2 α-Al2O3) content, resulting hardness, relative density (92.4%), compared BPR, which reached 97.2% significantly than MoCu alloys.