Strengthening strain-transformable β Ti-alloy via multi-phase nanostructuration

Multi-phase nanostructurations, using short-time thermal treatment (STT) at ω and α precipitation ranges (573 K–973 K), were applied on the strain-transformable β Ti-12Mo alloy with TRIP and TWIP effects (TRIP: Transformation induced Plasticity, TWIP: Twinning induced Plasticity). The aim is to study the evolution of the tensile properties and deformation mechanisms as a function of STT-induced nanostructurations. A series of multi-phase precipitations, i.e. athermal ω (ωath), isothermal ω (ωiso), nanoparticle-like α (αnano) and plate-like α (αeq), were obtained in metastable β matrix with strong strengthening effects. The nanostructurations via the multi-phase precipitations brought about important improvements of yielding stresses of tensile deformation. Microstructural investigations were performed before and after the deformations using transmission electron microscopy (TEM). The {112}〈111〉 twinning, {332}〈113〉 twinning and stress-induced martensitic (SIM) transformation were identified in the deformed samples. The evolution of the deformation mechanisms revealed the key roles of the multi-phase nanostructurations on the strengthening of strain-transformable Ti alloys. Two interesting nanostructurations at ωath/ωiso nanostructuration range and αnano/αeq range were highlighted for the promising potentials to preserve TRIP/TWIP effects in the strengthened alloys. [Display omitted] •Short-time thermal treatment (STT) induces multi-phase nanostructuration in Ti-12Mo alloy.•STT-induced nanostructuration can strengthen the β matrix in Ti-12Mo alloy.•STT-induced nanostructuration affects the formation of SIM α″ and deformation twins.•Two interesting nanostructurations can preserve TRIP/TWIP effect in Ti-12Mo alloy.