Abstract
The partial replacement of Ni by 30 at%Cu for the Pd40Ni40-xCuxP20 alloys was found to cause the drastic increase in the glass-forming ability as is evidenced from the decrease in the critical cooling rate for glass formation (Rc) to 1.5 K/s and the increase in the critical sample thickness for glass formation (tmax) to 40 mm. The Pd40Ni10Cu30P20 amorphous alloy exhibits the distinct glass transition, followed by the appearance of a wide supercooled liquid region (ΔTx(=Tx-Tg) reaching 95 K and then a single-stage crystallization. The differential thermal analysis indicates that the Pd-Ni-Cu-P alloy has a single stage melting reaction at 804 K. The resulting Tg/Tm is measured to be as high as 0.72. Considering that the Rc, tmax, ΔTx and Tg/Tm are 128 K/s, about 7 mm, 63 K and 0.66, respectively, for a Pd40Ni40P20 amorphous alloy with the largest glass-forming ability in previously reported Pd-based alloys, the present new Pd-Ni-Cu-P amorphous alloy is concluded to have a much larger glass-forming ability and a higher thermal stability of the supercooled liquid. The crystallization occurs through a single stage due to the precipitation of more than four kinds of crystalline phases and hence the necessity of long-range rearrangement of the constituent elements for the progress of the precipitation seems to cause the large glass-forming ability and the high thermal stability of the supercooled liquid through the retardation of crystallization. The finding of the new Pd-based amorphous alloy with the much larger glass-forming ability is important for the future development of basic science and engineering application of amorphous alloys.
Original language | English |
---|---|
Pages (from-to) | 1531-1539 |
Number of pages | 9 |
Journal | Materials Transactions, JIM |
Volume | 37 |
Issue number | 10 |
DOIs | |
Publication status | Published - 1996 |
Keywords
- Bulk amorphous alloys
- Continuous-cooling-transformation curve
- Copper mold casting
- High reduced glass-transition temperature
- Large glass-forming ability
- Low critical cooling rate
- Palladium-nickel-copper-phosphorus system
- Wide supercooled liquid region
ASJC Scopus subject areas
- Engineering(all)