Role of high-pressure high-temperature treatment in atomic diffusion and toughening of 47Zr-45Ti-5Al-3 V Alloy

• High pressure promotes atomic diffusion during HPHT treatment of Zr-Ti alloys. • High pressure reduced the diffusion activation energy of V atoms in the β phase . • Phase stability of β-Zr determine the deformation from TRIP to TWIP. • High-pressure and high-temperature treatment effectively toughening Zr-Ti alloys. This study integrated experimental observations and first-principles calculations to demonstrate that high pressure facilitates atomic diffusion during high-pressure high-temperature (HPHT) treatment of Zr-Ti alloys. As the pressure increases from 0 to 5 GPa, the activation energy for V atoms in the β-Zr phase decreases from 318.25 eV to 57.58 eV, promoting the outward diffusion of V atoms in primary β-Zr grains and reducing β-Zr phase stability. This results in a double-yielding phenomenon, wherein the deformation behavior transitions from dislocation slip in untreated samples to twinning-induced plasticity (TWIP) or transformation-induced plasticity (TRIP) in as-treated samples under elevated pressures, significantly enhancing compressive plasticity. The reduction in initial yield strength with increasing pressure further corroborates that high pressure enhances atomic diffusion. This work provides insights into the effects of high pressure on atomic diffusion, with implications for the microstructural design and control of advanced structural materials.