MODELING AND PREDICTION OF MECHANICAL-PROPERTIES FOR MATERIALS WITH HEXAGONAL SYMMETRY (ZINC, TITANIUM AND ZIRCONIUM ALLOYS)

In this work we have modelled Various mechanical properties for hexago nal materials having various textures and/or deformation mechanisms. T he main purpose of this work was to determine with great accuracy the active deformation mechanisms and to evaluate the corresponding CRSS r atios. This study-carried out by optical and electron microscopy-is ba sed on the statistical data obtained for the deformation mechanisms (f requency of occurrence) applying to each alloy. Though more sophistica ted models are available, we used-in a first approach-the relatively s imple Taylor model (constrained and relaxed variants) with the fairly reliable CRSS ratios we had previously assessed (accuracy around 10%) and used earlier for the modelling of the texture evolution. With thes e values, we then modelled the variation in the sheet plane of the yie ld stress, the plastic strain ratio, and the yield loci. The predicted curves were then compared with the experimental ones that had been dr awn, including the margin of experimental error. In the case of TA6V w e made a distinction between pyramidal [c + a](+) and [c + a](-) slip directions. The predicted yield loci of TA6V show the same asymmetry i n tension and compression as the experimental curves. (C) 1997 Acta me tallurgica Inc.