Physical and Mechanical Properties of Single Crystals of Co-Al-W Based Alloys with L1₂ Single-Phase and L1₂/fcc Two-Phase Microstructures

Abstract:

The values of all the three independent single-crystal elastic constants and polycrystalline elastic constants of Co3(Al,W) experimentally determined by resonance ultrasound spectroscopy at liquid helium temperature are 15~25% larger than those of Ni3(Al,Ta) but are considerably smaller than those previously calculated. Because of the large value of E111/E100 and cij of Co3(Al,W), two-phase microstructures with cuboidal L12 precipitates well aligned parallel to <100> and well faceted parallel to {100} are expected to form very easily in Co-base alloys, as confirmed indeed by experiment. Values of yield stress obtained for [001]-oriented L12/fcc two-phase single crystals moderately decrease with the increase in temperature up to 800°C and then decrease rapidly with temperature above 800°C without any anomaly in yield stress.

• Periodical: Materials Science Forum (Volumes 638-642)
• Pages: 1342-1347
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.638-642.1342
• Online since: January 2010
• Authors: Haruyuki Inui, Takashi Oohashi, Norihiko L. Okamoto, Kyosuke Kishida, Katsushi Tanaka
• Keywords: Cuboidal Precipitate, Elastic Property, L1₂ Compound, Microstructure, Strength

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