Abstract: The glass-forming ability and mechanical properties of metallic glasses and their composites are well known to be sensitive to the preparation conditions and are highly deteriorated by industrial preparing conditions such as low-purity raw materials and low vacuum. Here, we showed that a series of in-situ bulk metallic glass composites (BMGCs) which exhibit excellent ductility and segmental work hardening were successfully developed utilizing a high vacuum high-pressure die casting (HV-HPDC) technology along with industrial-grade raw materials. The tensile properties of these BMGCs are systematically investigated and correlated with the alloy microstructure. As compared with the copper mold suction casting method, the volume fraction difference of the dendrite phase for the BMGCs with the same composition is not significant when fabricated by the HV-HPDC, whereas the size of the β-phase is generally larger. In-situ BMGCs with the composition of Ti₄₈Zr₂₀(V_12/17Cu_5/17)₁₉Be₁₃ obtained by the HV-HPDC process show ductility up to 11.3% under tension at room temperature and exhibit a certain amount of work hardening. Two conditions need to be met to enable the BMGCs, which are prepared by vacuum die-casting to retain favorable ductility: (1) The volume fraction of β phase stays below 62% ± 2%; (2) The equiaxed crystals with a more uniform size in the range of 5-10 μm. Meanwhile, the results of the present study provided guidance for developing BMGCs with good ductile properties under industrial conditions.

Key words: Vacuum die casting, Bulk metallic glass composites, Mechanical properties, β-phase