PLASTIC-DEFORMATION OF ORDERED INTERMETALLIC ALLOYS - FUNDAMENTAL-ASPECTS

Fundamental aspects of plastic deformation in ordered intermetallic alloys are reviewed by directly comparing the temperature-dependent yield stresses of Ni3Al and Ni3Si (the L1(2) structure), NiAl and FeAl (the B2 structure), and TiAl and Ti3Al (non-cubic Ll(0) and DO19 structures, respectively). While the yield strength anomaly observed in Ni3Al is consistent with the prevailing dislocation models, that found in stoichiometric Ni3Si is not. The strong plastic anisotropy observed in NiAl stems from the high antiphase boundary energy, and that found in two-phase gamma-TiAl/alpha(2)-Ti3Al is due to the exceptionally high compressive yield strength along the c-axis of Ti3Al.