Modeling of strain gradient-dependent strengthening effect in grinding of boron-diffusion-hardened titanium alloy

Abstract

In grinding of the boron-diffusion-hardened titanium alloy, with the grinding speed increasing, the strain gradient-dependent strengthening (SGS) effect of TiB whiskers would become obvious, resulting in an improvement of the surface quality. To explore such SGS effect of TiB whiskers, a novel model of the strain gradient-dependent strengthening effect in the primary deformation zone was developed, and then a novel specific grinding energy model was further proposed to quantitatively estimate such SGS effect of TiB whiskers. It indicates that the above two models can adequately demonstrate the SGS effect of TiB whiskers in grinding the borided titanium alloy. The results demonstrate that the grinding performance of the borided titanium alloy was dominated not only by the grinding speed but also by the TiB whiskers. Due to high grinding speed (about 120 m/s) inclining to cause the maximum undeformed chip thickness reduced, when it was closed to the size of TiB whiskers, the SGS effect of TiB whiskers would become obvious, leading to an improvement of surface quality. Furthermore, when the size of TiB whiskers was closed to the sub-micron-scale, the enhanced SGS effect of the sub-micro-sized TiB whiskers tends to generate, causing the surface quality further improved.