Glass forming ability and mechanical properties on new Ni-based bulk metallic glasses

New Ni-Zr-Cu-Ti-Al bulk metallic glasses (BMGs) were fabricated on the basis of ternary Ni-Zr-Al alloys. The addition of Cu and Ti increased the glass-forming ability (GFA) of Ni-Zr-Al alloys. These BMGs exhibited high thermal stability and relatively large supercooled-liquid region. With the substitution of Ni by Cu from 0 to 19.2 at%, the GFA of Ni-Zr-Ti-Al alloys was enhanced and its glass transition temperature Tg, onset crystallization temperature Tx, and onset melting temperature Tm all decreased. When Cu content was 24 at%, the GFA decreased again. The BMG rod with a maximum diameter of 2 mm was fabricated in the Ni43.7Zr19.2Cu19.2Ti13.9Al4 alloy and the compression tests indicated that it had high fracture strength of about 2400 MPa, Young's modulus of 121 GPa, elastic strain of 0.02 and plastic strain of 0.009 at ambient temperature. (author)