Effect of Metastable Phase Content Controlled by Heat-Treatment on High Temperature Oxidation Performance of Directionally Solidified Ni-Si Hypereutectic Composites
Wei Li , Chunjuan Cui , Zhanpeng Liang , Wei Liu , Zhiqi Zhao , Haolin Li , Haijun Su , Lei Luo
Journal of Wuhan University of Technology Materials Science Edition ›› 2026, Vol. 41 ›› Issue (3) : 639 -649.
Different annealing heat treatment processes were performed on Ni-Si hypereutectic composites at the solidification rate of 40 µm/s to eliminate the metastable phase and the best heat treatment process was selected (annealing temperature 1 000 °C, holding time 4 h). The oxidation weight gain and oxide rate, oxide film morphology, and oxidation kinetics of Ni-Si hypereutectic composites were studied. Moreover, the formation mechanism of the oxide film was investigated through a thermodynamic analysis, specifically by calculating the change of Gibbs free energy associated with the oxidation reactions. It is found that the oxide resistance of the Ni-Si hypereutectic composite without metastable phase is better than that of the 67.9% content of the metastable phase. The surface of oxidized film is composed of granular NiO, while the underlying layer of oxidized film is composed of platelet-shaped SiO2 and spinel-like nickel silicate Ni2SiO4. Directionally solidified Ni-Si hypereutectic composites have potential applications in high temperature fields. However, Ni31Si12 metastable phase is inevitably formed due to the non-equilibrium solidification, which makes the overall properties of the material unstable.
directional solidification / Ni-Si hypereutectic composite / metastable phase / annealing heat treatment / high temperature oxidation
| [1] |
|
| [2] |
|
| [3] |
|
| [4] |
|
| [5] |
|
| [6] |
|
| [7] |
|
| [8] |
|
| [9] |
|
| [10] |
|
| [11] |
|
| [12] |
|
| [13] |
|
| [14] |
|
| [15] |
|
| [16] |
|
| [17] |
|
| [18] |
|
| [19] |
|
| [20] |
|
| [21] |
|
| [22] |
|
| [23] |
|
| [24] |
|
| [25] |
|
Wuhan University of Technology and Springer-Verlag GmbH Germany, Part of Springer Nature
/
| 〈 |
|
〉 |