EXOTHERMIC REACTIONS IN HOT EXPLOSIVELY COMPACTED Al-Ni COMPOSITES

摘要

Two series of nickel-coated aluminum (Al-Ni) powder compositions were consolidated to full or near-full density by a hot-explosive-compaction (HEC) technique. Mixtures of 78Al-22M at.% (63A1-37Ni wt.%) or 39 Al-61Ni at.% (23Al-77Ni wt.%) were placed in cylindrical containers, preheated to a range of temperatures from ambient to 1,000°C, and, once at a uniform temperature, explosively compacted into a 150-mm-long and 15-mm diameter rod-shaped billet using a cylindrical detonation arrangement. The resultant billets were sectioned and prepared for examination by optical and scanning electron microscopy (SEM). Energy dispersive x-ray spectroscopy (EDS), X-ray diffraction (XRD), and microhardness measurements were used to characterize the billet morphology, structure, and chemical composition. Analysis revealed that depending on the preheating temperature, the initial Al-Ni composition transformed into several aluminum nickelide (Al-Ni) intermetallics. The onset and nature of the shock-induced transformation from the precursors into the products are discussed.