Improvement of mechanical properties in MgCuYNdAg bulk metallic glasses with adding Mo particles

In this study, the Mg₅₈Cu_29.5Y₆Nd ₅Ag_1.5 bulk metallic glasses (BMGs) with superior glass forming ability are made by Cu-mold casting and injection casting processes. Critical rod size of the Mg₅₈Cu_29.5Y₆Nd ₅Ag_1.5 BMGs (base alloys) reached ∼4 mm in diameter. The results of Vickers indentation and compression tests of Mg ₅₈Cu_29.5Y₆Nd₅Ag_1.5 alloy reveal that the mechanical performance of the BMG base alloy is brittle. The highest fracture toughness and plastic strain of the base alloy are only ∼9 MPa m^1/2 and ∼0%, respectively. SEM observation is followed after the mechanical properties tests. It showed that the dominant patterns of the fracture surface are the featureless mirror-like and river-like regions. For enhancing the mechanical properties of the base alloys, porous Mo particles are added to form Mg₅₈Cu_29.5Y₆Nd₅Ag _1.5-Mo BMG composites (BMGCs). It is found that the fracture toughness and the fracture strength of the 30 vol.% Mo particles reinforced Mg₅₈Cu_29.5Y₆Nd₅Ag_1.5 BMGCs is promoted to ∼50 MPa m^1/2 and ∼1100 MPa. The observation of the fracture surface of Mg₅₈Cu_29.5Y ₆Nd₅Ag_1.5-30 vol.% Mo BMG composite via the compression test reveals that the shear bands and cracks propagation is resisted by the dispersion of Mo particles and secondary shear bands are formed during the plastic deformation. It is also observed that the fracture surface is occupied by vein-like pattern, instead of mirror-like region. Moreover, the plastic strain of the Mg₅₈Cu_29.5Y₆Nd ₅Ag_1.5-30 vol.% Mo BMG composite increased to ∼29%.