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

Abstract

New Mg–Cu–Ti–Y quaternary bulk metallic glasses (BMGs) with diameter of 2mm 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, 8at.%) alloys possess completely amorphous structures and large supercooled liquid region (59–64K). 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 879MPa, 3.04%, 347 and 34GPa, respectively, which are much superior to the as-cast Ti-free Mg60Cu30Y10 BMG. The as-cast alloys' fracture surface morphologies and dominant fracture behaviors have also been characterized and explained in detail.