High throughput construction for the deformation mechanism diagram and dynamic recrystallization of a bimodal-sized particle-reinforced Ti-2.5Zr-2Al-1(Si,C) titanium alloy

Abstract

An in situ autogenous particle-reinforced Ti-2.5Zr-2Al-1(Si,C) titanium alloy is prepared by vacuum induction melting. The wide range of an effective strain between 0.2 and 1.2 and the corresponding microstructure are obtained by the double-cone high-throughput compression test and finite element simulation. The deformation mechanism diagram with strains of 0.2–1.2 and strain rates of 0.7–1.5 s⁻¹ at 900°C is constructed. When the strain rate is 1.3 s⁻¹, dynamic recovery occurs in the small strain range (<0.377), dynamic recrystallization (DRX) occurs in the medium strain range (0.377–1.182), and deformation instability occurs in the large strain range (>1.182), resulting in the deformation bands. High-angle annular dark field and high-resolution transmission electron microscopy are used to determine the existence of bimodal particle distribution, namely micron-scale TiC particles and nano-scale Ti₅Si₃ and (Zr, Si) particles. The average radius of the (Zr, Si) nanoparticles measured by small angle neutron scattering is 19.3 nm, and the volume fraction is 0.35%. DRX grains with an average size of 0.49 μm are obtained at 900°C, strain rate of 1.3 s⁻¹, and strain of about 0.6. Micron-scale particles stimulated DRX nucleation, while nanoscale particles hindered the growth of new grains, resulting in grain refinement.