Thermo-formability Enhancement in titanium matrix composites by hydrogen microalloying

In this investigation, we utilize melt hydrogenation technology to produce hydrogen microalloyed Ti–6Al–4V matrix composites reinforced with in situ synthesized TiB ceramic whiskers, aiming to enhance their thermo-formability. The study elucidates the effects of varying hydrogen concentrations on the microstructural evolution and hot deformation behavior of the composites. Experimental observations indicate that melt hydrogenation leads to grain refinement and enhances load transfer at the TiBw-matrix interface. Thermal compression tests were conducted at a strain rate of 0.01 s⁻¹ across temperatures of 750 °C, 800 °C, 850 °C, and 900 °C. The results reveal that the composite containing 5.31 × 10⁻² wt% hydrogen undergoes hardening, attributed to a strengthened network and finer lamellae resulting from hydrogen incorporation. In contrast, the composite with 11.50 × 10⁻² wt% hydrogen exhibits softening, linked to a more homogeneous distribution of phases and dynamic recrystallization (DRX). Both types of hydrogenated composites demonstrate good deformation coordination, enhanced hot workability, and reduced defect densities, highlighting the potential of hydrogen microalloying as a strategy for improving the thermo-formability of titanium matrix composites.