Hypercooling and thermodynamic properties of liquid Ni-Fe alloys

Bingbo Wei, Changxing Dong

科研成果: 期刊稿件文章同行评审

2 引用 (Scopus)

摘要

Ni-10% Fe and Ni-35% Fe alloy melts were undercooled with glass fluxing technique by 371 (0. 90 ΔTh) and 343 K (0. 91 ΔTh). Their hypercooling limits ΔTh were determined to be 413 and 376 K respectively. A new method to measure the integral mean specific heat CpL of undercooled metallic melts was developed according to the definition of hypercooling. That is, one can take CpL as the ratio of latent heat of fusion ΔHm to hypercooling limit ΔTh, provided that the latter two physical parameters have been obtained through experiments. The CpL values of the above Ni - Fe alloys were found to be 41. 0 and 40. 7 J/ (mol · K). Theoretical calculations were also carried out to reveal the relationships of enthalpy change ΔHLS, entropy change ΔSLS, Gibbs free energy change ΔGLS and crystal nucleation rate I during rapid solidification vs undercooling. Although the maximum undercoolings achieved by both Ni - Fe alloys have exceeded the critical level of 0.2 TL, the calculated results indicate that heterogeneous nucleation must have taken place in preference to homogeneous nucleation. Those heterogeneous nucleants with a wetting angle range of 53 ° < θ < 80 ° played the dominating role to prevent Ni - Fe alloys from further approaching their hypercooling limits.

源语言英语
页(从-至)362
页数1
期刊Jinshu Xuebao/Acta Metallurgica Sinica
32
4
出版状态已出版 - 1996

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