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Published December 1987 | public
Journal Article

Microstructural modifications in a dynamically consolidated microcrystalline nickel titanium alloy powder

Abstract

Spherically shaped, microcrystalline NiTi alloy powder with both nonhomogeneous particle-size distribution (2 to 60μm diameter) and chemical composition, was consolidated with a shock input energy of 316 kJ kg%^(−1). Upon shock compaction, the two-phase NiTi powder particles (containing 45wt% Ti and 65 wt% Ti) were bonded together, generally by interparticle melting and subsequent welding. The melted material at interparticle regions was observed to have rapidly solidified to largely amorphous and/or microcrystalline phases. Particle interiors were also subjected to extensive plastic deformation which resulted in deformation twinning, grain elongation and some recrystallization to defect-free grains. Unique microstructural modifications occurring due to inhomogeneous thermal and mechanical processing during the dynamic consolidation process, are reported here.

Additional Information

© 1987 Chapman and Hall Ltd. Received 20 February and accepted 29 April 1987. This work was supported in part by the National Science Foundation under grant no. DMR-8315214 and the CalTech Program in Advanced Technologies sponsored by Aerojet General, General Motors, GTE, and TRW. The NiTi alloy powder was obtained from Special Metals Corporation, New Hartford, New York. We thank Michael A. Long for help with the compaction experiments and Randy Heuser for performing the EMPA work. CalTech Division of Geological and Planetary Sciences Contribution no. 4434.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023