Slip analysis and mechanical deformation behavior in dual-phase titanium alloy: Integrating crystal plasticity simulations with in-situ micro-compression

The strengthening effects of primary α grains in titanium alloys were systematically investigated by integrating micropillar compression tests and crystal plasticity simulations. This study focused on the deformation behavior of dual-phase micropillars consisting of a single primary α grain and a single-crystal β matrix. During compression, these micropillars exhibited two slip modes, i.e., single- and multi-slip features. Slip analysis was performed based on the compressed morphology of the pillars and the Schmid factors. It was found that the first slip step observed in multi-slip pillars was not attributed to the slip system with the largest Schmid factor. To validate the experimental findings, numerical simulations using crystal plasticity models were conducted. The simulation results accurately reproduced the engineering stress-strain responses and allowed for a comparison of the distribution of von Mises stress and cumulative shear strain between the dual-phase and single-β phase pillars. Also, the stress concentration induced by α precipitates affects the stress distribution and leads to heterogeneous deformation within the micropillars, correlating with the observed slip modes. The experimental and numerical results will provide a further understanding of meso-scale heterogeneous deformation behaviors and offer insights into the microstructure-properties relationship in titanium alloys.