COMPLIANCE TO SCHMID'S LAW IN THE STRESS ANOMALY REGIME OF BINARY STOICHIOMETRIC Ni_3Al

摘要

Using single crystals of binary stoichiometric Ni_3Al, the orientation dependence of the critical resolved shear stress (CRSS) for {111}(101) slip and the tension/compression (T/C) asymmetry were studied in the yield stress anomaly regime. Unlike the case in ternary alloys, it was found that Schmid's law holds and the T/C asymmetry vanishes in stoichiometric Ni_3Al. This indicates that plastic deformation occurs according to Schmid's law in the highly ordered state. Also, the violation of Schmid's law and the T/C asymmetry, which were believed to be inherent to the stress anomaly so far, are considered to be additional effects due to the anti-site defects or specific ternary elements. The results are consistent with the idea that the CRSS is controlled by the dislocation multiplication in (111).