Development and microstructure optimization of Mg-based metallic glass matrix composites with in situ B2-NiTi dispersoids

• A novel process was designed to fabricated bulk metallic glass matrix composite.
• In situ B2-NiTi reinforced Mg-based metallic glass matrix composite was fabricated.
• The composite showed good plasticity and work hardening.
• Microstructure was optimized to achieve better mechanical properties.
• A new model of second particle effects on plasticity of the composite was developed.

In this paper, we designed a novel processing method and successfully developed in situ precipitated B2-NiTi shape-memory-alloy reinforced Mg-based bulk metallic glass matrix composites (BMGMCs). The composites exhibited improved fracture strength in both compressive and flexural modes and large plastic deformation in compressive mode compared with those of its monolithic glassy counterpart. The stress-induced martensitic transformation of B2-NiTi in this system caused the composite to exhibit work-hardening behavior, especially during compression. The microstructure of the composite was optimized by decreasing the size and increasing the volume fraction of the B2-NiTi phase, to obtain better mechanical properties. This novel in situ method is applicable to fabricating various BMGMCs, making it a breakthrough for designing ductile work-hardenable BMGMCs.

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