Electron Backscatter Diffraction Investigation on Microstructure Evolution of TiB2(p)/Al-Cu Composite after Single-Pass Equal Channel Angular Pressing for Formability Assessment

Abstract

In this study, the in situ 4 wt.% TiB_2(p)/Al-Cu composite was prepared through a mixed salt reaction method. To evaluate its formability, hot isothermal compression tests were performed using a Gleeble−3500 system in a temperature range of 480-510 °C and a strain rate range of 0.1-10 s⁻¹. A constitutive model of the composites with strain compensation was established, and the true stress–strain curves revealed that the composite exhibited favorable formability at 510 °C. Additionally, single-pass equal channel angular pressing (ECAP) processes were conducted at room temperature and 510 °C to investigate the microstructure evolution of the composite. The distribution of TiB₂ particles was found to be influenced by deformation temperature, while the microstructural characteristics of the aluminum matrix were minimally affected. Furthermore, a comparison between the as-cast composite and the deformed composites revealed the presence of different preferred orientations in the two conditions, and the corresponding paths of texture evolution were estimated accordingly. Remarkably, after undergoing single-pass ECAP, the Schmid factors of composites remained nearly unchanged, demonstrating that deformed composites were still appropriate for processing and as such demonstrating a potential route also for formability assessment.