Effect of Milling Time on the Morphological Evolution of Titanium Alloy Powder

This work examines the influence of disc milling duration on the morphological transformation and crystal reorientation of titanium alloy powder with a particle size below 90 µm. The disc milling time was varied from 2 mins to 10 mins, the morphological features of the powders were characterized through the scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD). From the results, milling time had a significant effect on the morphology and the orientation of phases in the titanium alloy powder. The SEM images revealed a plate-like shape compared with the un-milled powder with a spheriodal shape. It was also observed that the flattening of the particles increased with milling time. This suggests that the powder is ductile. The oxygen content of the particles increased from 3.4 wt. % before milling to above 10 wt. %. XRD results showed that the milling time did not bring about a new phase and in the position of maximum diffraction intensity, which occurred at 2θ equal to approximately 40.6°. However, there was a decrease in the crystallite size while the lattice strain became higher as milling time increased.