Compliance to Schmid's law in the stress anomaly regime of binary stoichiometric Ni3Al

Using single crystals of binary stoichiometric Ni3Al, the orientation depen dence of the critical resolved shear stress (CRSS) for {111}{101} slip and the tension/compression (T/C) asymmetry were studied in the yield stress an omaly regime. Unlike the case in ternary alloys, it was found that Schmid's law holds and the T/C asymmetry vanishes in stoichiometric Ni3Al. This ind icates that plastic deformation occurs according to Schmid's law in the hig hly ordered state. Also, the Violation of Schmid's law and the T/C asymmetr y, which were believed to be inherent to the stress anomaly so far, are con sidered to be additional effects due to the anti-site defects or specific t ernary elements. The results are consistent with the idea that the CRSS is controlled by the dislocation multiplication in (111). (C) 1999 Acta Metall urgica Inc. Published by Elsevier Science Ltd. All rights reserved.