Evolution of Microstructure and Crystallographic Texture in Severely Deformed FeCoNiAlTi Multicomponent Alloy

Abstract

The evolution of microstructure, texture, phase composition, and dislocation density distribution in Fe-based shape memory alloys processed by high-pressure torsion (HPT) at room temperature was investigated using synchrotron radiation and electron backscatter diffraction. The initial material was a hydrostatically extruded sample that underwent additional heat treatment. Before HPT deformation, the disks were heat treated at 1200°C for 5 mins. to relieve the stresses. The starting Fe-based material was characterized by a strong fibre <111> texture and coarse columnar grains with an average size of approximately 200 μm. The HPT process alters the initial <111> strong fibre texture to a typical shear texture with dominating B, B–, A1* and A2* components. As deformation proceeds marginal precipitation of β phase occurs. The precipitation process seems to be related to the shear magnitude, as the volume fraction of β phase increased linearly with shear. Furthermore, the precipitates produced by HPT form a typical texture for bcc metals with F and J1 components.