Microstructure and mechanical properties of Mo2Ni3Si-Al2O3 nanocomposite synthesized by mechanical alloying

Mo2Ni3Si-Al2O3 nanocomposite was synthesized using MoO3, Ni, Si, and Al as starting materials by mechanical alloying. The mechanically alloyed powders were consolidated by hot pressing. The morphology and structural evolution of composite powders were investigated by scanning electron microscopy (SEM) and x-ray diffraction (XRD). The microstructure and mechanical properties of the consolidated products were studied in detail. The results showed that Mo2Ni3Si-Al2O3 composite was obtained after 10 h of milling. The reaction mechanism mechanically induced self propagating reaction. The mean grain size of Mo2Ni3Si and Al2O3 after milling for 20 h were 15.9 and 32.4 nm, respectively. The Mo2Ni3Si-Al2O3 composite powders are stable during an annealing at 1000 degrees C. After consolidation, Mo2Ni3Si-Al2O3 composite has a high density (96.3%) and fine-grain (microns and submicrometer range). The hardness, flexure strength, and fracture toughness of Mo2Ni3Si-Al2O3 composite are 13 GPa, 533 MPa, and 6.29 MPam(1/2), respectively. Meanwhile, the composite has higher strength at high temperature, and the strength remains stable up to 1000 degrees C (about 513 MPa).