Enhanced tensile strength and ductility of bulk metallic glasses Zr52.5Cu17.9Al10Ni14.6Ti5 via high-pressure torsion

Zr52.5Cu17.9Al10Ni14.6Ti5 (Vit105) Bulk metallic glass is processed by High-Pressure Torsion up to 30 rotations at room temperature, showing simultaneous enhancement of both strength (2023 MPa) and ductility (0.45%). Nano-crystal precipitates with an average size of 45 nm inside the amorphous matrix are observed after 30 turns HPT. Free volume increases from similar to 0.9030 angstrom(3) (as cast) to similar to 0.9275 angstrom(3) after 30 turn HPT alloy with 2.83% (by volume) of nanocrystal precipitates. Strengthening due to precipitation after 30 turns HPT comply with the phase mixture model. The synergetic effect of free volume and nanocrystal precipitation on the ductility of amorphouscrystallite composite is quantitatively approached through modelling. By implementing the model, a ductilization window between bottom limit and top limit of the inter-crystallite spacing w.r.t the free volume is established, elucidating the necessary conditions required to obtain plasticity in amorphous-crystalline composites.

Automated summary

Vit105 bulk metallic glass processed by High-Pressure Torsion shows simultaneous enhancement of strength and ductility, with nano-crystal precipitates observed after 30 rotations. The increase in free volume and the strengthening due to precipitation comply with the phase mixture model. A ductilization window for amorphous-crystalline composites is established through quantitative modeling of the synergetic effect of free volume and nanocrystal precipitation on ductility.