Development and Characterization of Nano-Al2O3, Cr2O3, and TiO2 Dispersed Mo Alloys Fabricated by Powder Metallurgy

The study reports the fabrication of 1.0 wt.% nano-Al2O3, Cr2O3, and TiO2 dispersed Mo alloys by mechanical alloying for 20 h and conventional sintering at 1450 degrees C with 2 h of soaking period. The 20-h milled powder evidences the encapsulation of oxide particles inside Mo particle. High-resolution transmission electron microscopy (HRTEM) reveals that oxide particles are in-coherent with Mo matrix in Mo-Al2O3 alloy. X-ray diffraction study (XRD) evidences MoO2 phase formation and oxide phases in the sintered alloys. Mo-TiO2 alloy exhibits maximum sintered density compared to other alloys. The investigation reports an excellent bulk Vickers hardness of 645 HV for Mo-Al2O3 alloy. Maximum compressive strength and % compressive strain at maximum compressive load are evident in Mo-Cr2O3 alloy. Mo-Al2O3 and Mo-Cr2O3 alloys show enhanced wear resistance against Mo-TiO2 alloy, owing to the higher fraction of MoO2 oxide precipitation. The oxides hinder the dislocation motion, responsible for achieving improved wear resistance. Mo-Al2O3 alloy records lower oxidation and spallation/blistering at 1000 degrees C for 10 h compared to other alloys.