The dependence of the iron–carbon eutectic transition temperature on thermal history and its implications for thermometry

• Published in: Journal of alloys and compounds Vol. 452; no. 1; pp. 61 - 66
• Main Authors: Sasajima, N., Yamada, Y., Wang, Y., Bloembergen, P., Wang, T., Le Coze, J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 06.03.2008; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fixed point; High temperature; Materials science; Metal–carbon eutectic; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phase diagrams of metals and alloys; Physics; Radiation thermometer; Temperature standard; Metal–carbon eutectic; Temperature standard; High temperature; Radiation thermometer; Fixed point; Annealing; Melting; Growth rate; Liquidus; Thermometry; Iron; Carbon; Solidification; Impurities; Temperature effects; Eutectic transformation; Metal-carbon eutectic; Melts
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2006.12.158

The melting behavior of the eutectic Fe–C fixed point was investigated as a function of the thermal history prior to melting using degassed and non-degassed Fe–C cells. The liquidus temperature and the melting range depend on the preceding growth rate: slower freezing entails a higher liquidus temperature and a smaller melting range. Annealing at temperatures just below the eutectic temperature has similar effects. The inflection point of the melting plateau and the maximum temperature of the freezing plateau showed a linear variation with the square root of the growth rate during the (preceding) freeze and this variation is approximately five times smaller for the melt than for the freeze. No clear evidence of the effect of gaseous impurities could be detected on the shape of the melting plateau obtained in conjunction with the lowest growth rate. However, both the inflection point of the melting plateau and the maximum temperature of the freezing plateau showed a larger dependence on the growth rate for the degassed cell.