The thermal explosion synthesis of AlNi monitored by neutron thermodiffractometry

The synthesis of AlNi from thermally activated equimolar powder mixtures of aluminium and nickel was monitored in situ and acquired diffraction patterns every 2 s or less. The analysis of diffraction patterns (lambda = 1.3112 angstrom) permitted establishment of its kinetics, which could be modeled according to an equation expressed as kt = [alpha/(1 - alpha)](3/2). From 1530 to approximate to 600 degrees C an activation energy of 9 +/- 2 kJ mol(-1) was estimated. Also, the crystallite size evolution on cooling was established to vary from approximate to 14 nm at 1530 degrees C to approximate to 28 nm at 180 degrees C. Finally, the reaction was found to occur through the melting of aluminium and the subsequent dissolving of nickel to form the polycrystalline single-phase product, AlNi. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.