Effects of milling on the microstructure and hardness of Al2NbTi3V2Zr high-entropy alloy

Lightweight Al2NbTi3V2Zr alloy was fabricated through mechanical milling and vacuum hot pressing. The effects of milling on the microstructure, phase evolution, and hardness of the fabricated alloy were investigated. High-energy (HE) milling decreased the size of crystalline grains and activated the powders for subsequent sintering. HE-annealed powders at above 900 degrees C and all sintered bulks consisted of body-centered cubic (BCC) and intermetallics alpha and beta. Low-energy (LE) milling only provided homogeneity to the powders. LE bulks exhibited a microstructure similar to that of HE bulks at 1450 degrees C-1550 degrees C. The hardness of the HE bulk was higher than that of the LE bulk and exhibited a peak value of 781 HV at 1250 degrees C. All Al2NbTi3V2Zr bulks possessed low density ranging from 5.05 g/cm(3) to 5.25 g/cm(3). Two empirical equations for hardness of the bulks were proposed for the BCC matrix bulks and simple cubic matrix bulks respectively and the estimated results are consistent with the experimental measurements. (C) 2016 Elsevier Ltd. All rights reserved.