Mechanical behavior of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glasses

The thermal stability and the mechanical behavior of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glasses (BMGs) were investigated by differential scanning calorimetry, uniaxial compressive test, ultrasonic method, and nanoindentation. The substitution of Zr by Be significantly improved the thermal stability of the amorphous phase, exhibited by a wide supercooled liquid region of 116 K. The Be containing BMG exhibited a compressive strength of 1780 MPa, and in particular a high plastic strain of about 6%. The simultaneous operation of multiple shear bands during plastic deformation in Zr52.5Al10Ni10Cu15.5 BMG is proved by the less pronounced serrated flow during the loading process in the compression and nanoindentation, as well as the fracture surface morphologies. A high Debye temperature derived from the ultrasonic measurements indicates a condensed atomic arrangement in the Be containing BMG, and may responsible for the high thermal stability.