The mechanics of High Pressure Compressive Shearing with application to ARMCO® steel

Abstract In High Pressure Shearing (HPS) a flat sample is subjected to large shear strain by displacing one of its flat surfaces with respect to the other under high compressive force. The process is driven by non-sliding friction provided by the large compressive stress. The HPS process was first proposed by Fujioka and Horita [Materials transactions, 50 (2009) 930–933], and was applied to aluminum strips; upscaling was also developed. In the present work we introduce a modified version of HPS where the compression strain is relevant, so the new process is called High Pressure Compressive Shearing (HPCS). In HPCS, the experiments are conducted similarly to HPS but with the addition of a confining-pressure and more compression strain to increase the shear strain. This paper presents the mechanical analysis of stress and strain states during HPCS and demonstrates in situ measurements of stress-strain relations in ARMCO® steel subject to HPCS at room temperature up to an equivalent strain of 33.3. The strain hardening characteristics, the texture and the microstructure were analyzed. It has been shown that compression during HPCS results in a non-hydrostatic stress state and that ultimate steady state of grain fragmentation can be readily reached by HPCS.