Effect of particle morphology on the flowability of HDH Ti powders treated by high temperature ball milling

[Display omitted] •Morphology of low cost HDH titanium powder seriously affects its flowability.•A novel technique to improve powder morphology for enhancing its flowability.•Quantitative correlation of powder flowability and morphology was established.•Flowability increases with a smaller fractal dimension and/or larger circularity. The metal powder flowability determined by powder characteristics significantly influences on the final parts manufactured by additive manufacturing (AM). Among the characteristics, the individually effect of morphology on its flowability still is not comprehensively evaluated. In this study, the effect of morphology on the flowability of hydride-dehydrate titanium (HDH Ti) powder treated by high temperature ball milling (HTBM) was investigated systematically using the fractal dimension and shape factors, i.e., circularity, elongation, compactness and convexity. The results of HTBM show that the modified HDH Ti powder with a mass flow rate of 48.1 ± 0.3 s/50 g and the angle of repose (AOR) of 38.88 ± 0.5°. The fractal dimension of powder plays a main role on the flowability, which increase in the decrease of it. The box plot and Pearson correlation coefficient of shape factors indicate that only circularity is strong correlation with flowability, which increases with it. The regression model of flowability expressed with fractal dimension and circularity shows the adjusted R2 value of 0.991, which is good agreement with the experiment. Taken together, this study provides a general guide to evaluate the powder flowability based on the morphology.