2001 Volume 42 Issue 5 Pages 886-889
The glass-forming ability in Ni57−xTi23Zr15Si5Pdx (x=0, 5, 10, 12.5, 15 and 20) alloys as a function of Pd concentration was examined by melt-spinning and copper mold casting methods. All the melt-spun ribbons are in a glassy state. ΔTx(ΔTx=Tx−Tg) and Tg⁄Tm were used to evaluate the glass-forming ability, where Tg,Tx and Tm represent the glass transition, crystallization and melting temperatures, respectively. The observation of large ΔTx and Tg⁄Tm values in the 12.5 at%Pd alloy implies a high glass-forming ability. At this composition, a cylindrical bulk alloy with a diameter of 2 mm was verified to be in a single glassy state. For the bulk cylinder of 3 mm in diameter, the volume fraction of glassy phase is approximately 92%. The compression fracture strength (σ) and Vickers hardness (Hv) of the bulk glassy alloy are 2100 MPa and 620, respectively. These results demonstrate the good mechanical performance of the present Ni-based bulk glassy alloy, which is prominent for future application.