Effects of load partitioning and texture on the plastic anisotropy of duplex stainless steel alloys under quasi-static loading conditions

Abstract

The plastic anisotropies of two hot-rolled Lean Duplex Stainless Steels (commercially known as LDX 2101 and LDX 2404) were investigated by applying compressive strains, at 10−3 s−1 rate, along the rolling- and transverse-directions (RD and TD). The microstructural changes were elucidated by Electron Backscatter Diffraction (EBSD) as a function of strain level and loading direction. In both alloy grades, the austenite phase shows a weaker texture development than the ferrite phase; the later develops {001}<110> and {110}<110> textures in LDX 2101 and LDX 2404 alloys, respectively. Also, in both alloys, the yield stress along the TD is larger by 10% than along the RD. Anisotropies are also detected in the rate of property changes with deformations; after 30% true strain, the flow stress along the RD in LDX 2101 alloy starts exceeding the stress along the TD. Microstructural studies indicate that the load partitioning, grains shape, phase boundaries and austenite to martensite phase transformations are the origins of the anisotropic phenomena in LDX 2101 alloy, whereas the crystallographic texture of ferrite phase, phase boundaries and load partitioning are the plausible origins of plastic anisotropies in LDX 2404 alloy.