MECHANICAL ANISOTROPY AND CRYSTALLOGRAPHIC TEXTURE IN TiAlMn ALLOY SHEET

Abstract

ABSTRACT Hexagonal close packed metals and alloys exhibit preferred orientations following thermo-mechanical treatments which result in anisotropic physical, magnetic and mechanical properties. The anisotropic nature of these materials may either be beneficial or detrimental depending on the specific application(s) of these textured materials. We report here the recent study on the crystallographic texture and mechanical anisotropy of a TiAlMn sheet. The crystallographic texture of the sheet was characterized using both the inverse and direct pole figures. The inverse pole figures were determined along the three orthogonal directions of the sheet from which the texture coefficients (TCs) and f-factors were evaluated. C rystallite o rientation d istribution f unctions were derived from the pole figure data and the predominant ideal orientations in the Euler plots were identified. The anisotropic mechanical properties were investigated using gridded tensile samples along the rolling (RD) and transverse (TD) directions of the sheet and the variations of width contractions with length elongations were determined. The contractile strain ratios (CSRs), R and P , were evaluated from these data. These CSRs are also the mechanical anisotropy parameters appearing in the modified Hill's formulation for the generalized stress, and the ratio of the strengths along the RD and TD derived from the experiments was correlated with the generalized stress formulation. Crystal plasticity models based on slip on the prism, basal and pyramidal slip system were applied with the derived CODF, and the model predictions are correlated with experimental results.