Reactivity of Aluminum-Based Mixtures with Early Transition Metals

Report No. ARL-TR-7027
Authors: Laszlo J Kecskes and Kenneth F Plunkett
Date/Pages: August 2014; 90 pages
Abstract: Equiatomic powder mixtures of Al and the early transition metals in Groups IV and V (i.e., titanium [Ti], zirconium [Zr], and hafnium [Hf]; and vanadium [V], niobium [Nb], and tantalum [Ta]) were prepared by high-energy mechanical alloying. Blends were subjected to microscopy and differential thermal analysis to systematically investigate the efficiency of conversion from reactants to products. Each of the aluminum (Al)-X blends was created by mechanically milling pure elemental powders with 1.5 weight-percent stearic acid to prevent cold welding to the milling vials internal walls during the blending process. The as-milled powders were analyzed via Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction Analysis (XRD), and Differential Scanning Calorimetry (DSC) to determine the effect of milling time on the total heat released. These analyses were performed prior and after DSC to compare the morphologies of the reactants and products, as well as to identify the bulk phases present in the product as they relate to the equilibrium phase diagram for that particular mixture. The DSC analysis was performed to measure and determine the total energy released from the mixtures while being heated to 1,000 °C at 10 K/min.
Distribution: Approved for public release
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Last Update / Reviewed: August 1, 2014