A strategy to design Ti-based in-situ bulk metallic glass composites containing controllable volume fraction and composition of the dendrite phase using conventional titanium alloy Ti–6Al–4V

Abstract

Up to now, the composition design in the field of Ti-based in-situ dendrite reinforced bulk metallic glass composites (BMGCs) has been a great challenge. In this work, a simple but effective strategy is proposed to tailor the dendrite composition and volume fraction by using conventional Titanium alloy Ti–6Al–4V, and a series of in-situ dendrite reinforced BMGCs (Z1-Z4) are prepared based on it. The dendrite volume fraction can be adjusted by changing the proportion of the Titanium alloy Ti–6Al–4V, while the compositions of the dendrites are highly correlated with Ti–6Al–4V. In these alloys, with the increase of the mass percent of the added Titanium alloy Ti–6Al–4V, the volume fraction of the dendrite phase increases monotonically from Z1 to Z4 alloy. Z1 alloy behaves like a BMG with a high yield strength and limited plasticity due to its small dendrite size. Z2-Z4 alloys show excellent plasticity and significant work-hardening ability, because the dendrite size is appropriate and the dendrites undergo stress-induced martensite transformation during compression. From Z2 to Z4 alloy, with the increase of dendrite volume fraction from 56% to 78%, the yield strength does not decrease, which is due to the gradually enhanced stability of the dendrites. This composition design strategy is effective and universal, which can provide a new perspective for the composition design and development of TiZr-based in-situ dendrite reinforced BMGCs.