Study on the formation of new Mg–Cu–Ti–Y quaternary bulk metallic glasses with high mechanical strength

New Mg–Cu–Ti–Y quaternary bulk metallic glasses (BMGs) with diameter of 2 mm have been designed and successfully fabricated by conventional copper mold casting method. The X-ray diffractometer (XRD) and differential scanning calorimeter (DSC) examinations indicate that the as-cast Ti-containing Mg60Cu30 − xTixY10 (x = 3, 5, 8 at.%) alloys possess completely amorphous structures and large supercooled liquid region (59–64 K). The mechanical property testings demonstrate that this kind of new BMGs also have high compressive fracture strength (σf), big elastic strain (εe), high Vickers hardness (Hv) and low elastic modulus (E). Thereinto, the σf, εe, Hv and E values of the as-cast Mg60Cu27Ti3Y10 BMG sample reach up to 879 MPa, 3.04%, 347 and 34 GPa, respectively, which are much superior to the as-cast Ti-free Mg60Cu30Y10 BMG. The as-cast alloysʹ fracture surface morphologies and dominant fracture behaviors have also been characterized and explained in detail.