Influence of rotating speed on mechanical alloying behavior of the elemental powder blends of Nb-Ti-Si based alloy during ball milling process

The elemental powder mixtures with the nominal composition of Nb-20Ti-15Si-5Cr-3Hf- 3Al (at. %) were ball milled via QM-1SP4-CL planetary ball-milling machine at different rotating speed (300, 400 and 500 rpm). The corresponding mechanical alloying behaviors of the powder blends, including the evolutions of their phase constituent, microstructure, size and morphology, have been analyzed by XRD, SEM and EDS. The results showed that with increasing rotating speed, the particle was remarkably refined and spheroidized, and meanwhile, the grain size decreased, accompanied with an improved microstrain. Herein, a lamellar microstructure of particles formed at the rotating speed of 300 rpm, and became finer with increasing the rotating speed up to 400 rpm. When further increasing the rotating speed up to 500 rpm, the homogenous microstructure composed of a supersaturated Nb solid solution (Nbss) finally formed.