Deciphering the Possible Role of Strain Path on the Evolution of Microstructure, Texture, and Magnetic Properties in a Fe-Cr-Ni Alloy

Abstract

In the present work, the influence of strain path on the evolution of microstructure, crystallographic texture, and magnetic properties of a two-phase Fe-Cr-Ni alloy was investigated. The Fe-Cr-Ni alloy had nearly equal proportion of austenite and ferrite and was cold rolled up to a true strain of 1.6 (thickness reduction) using two different strain paths—unidirectional rolling and multi-step cross rolling. The microstructures were characterized by scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD), while crystallographic textures were determined using X-ray diffraction. For magnetic characterization, B-H loops and M-H curves were measured and magnetic force microscopy was performed. After unidirectional rolling, ferrite showed the presence of strong α-fiber (rolling direction, RD//〈110〉) and austenite showed strong brass type texture (consisting of Brass (Bs) ({110}〈112〉), Goss ({110}〈001〉), and S ({123}〈634〉)). After multi-step cross rolling, strong rotated cube ({100}〈110〉) was developed in ferrite, while austenite showed ND (normal direction) rotated brass (~ 10 deg) texture. The strain-induced martensite (SIM) was found to be higher in unidirectionally rolled samples than multi-step cross-rolled samples. The coherently diffracting domain size, micro-strain, coercivity, and core loss also showed a strong correlation with strain and strain path. More strain was partitioned into austenite than ferrite during deformation (unidirectional as well as cross rolling). Further, the strain partitioning (in both austenite and ferrite) was found to be higher in unidirectionally rolled samples.