Bulk Glassy Alloys with Low Liquidus Temperature in Pt-Cu-P System
2003; Volume: 44; Issue: 6 Linguagem: Inglês
10.2320/matertrans.44.1143
ISSN1347-5320
Autores Tópico(s)Glass properties and applications
ResumoBulk glassy alloys with low values of liquidus temperature (Tl) and glass transition temperature (Tg) as well as high Tg⁄Tl were formed at Pt60Cu20P20. Glassy alloys in Pt80−xCuxP20 system were formed over the whole composition range up to 35 at%Cu examined in the present study. The Tg increases significantly with increasing Cu content, shows a maximum value of 522 K at 20%Cu and then decreases slightly with further increase in Cu content. On the other hand, the crystallization temperature (Tx) increases monotonously with increasing Cu content up to 25 at%Cu and then becomes saturated, leading to a monotonous increase in ΔTx(=Tx−Tg) from 25 K at 0%Cu to 83 K at 35 at%Cu. All the ternary glassy alloys crystallize through a single-stage exothermic reaction, accompanied by the precipitation of mixed Pt5P2, Cu3P and unknown phases. The 20%Cu-containing alloy has the lowest Tl of 854 K as well as the smallest temperature interval of 21 K between Tl and melting temperature (Tm) and hence the highest Tg⁄Tl of 0.61 is obtained for the 20%Cu alloy. The high Tg⁄Tl as well as the low Tl has enabled us to form bulk glassy alloy rods with diameters up to at least 12 mm by water quenching. The synthesis of the Pt–Cu–P glassy alloys with the low values of Tg and Tl and the large ΔTx is important for future development as precision materials for nano-technology which can be deformed through viscous flow.
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