Thermodynamic analysis of the iron-copper system I: The stable and metastable phase equilibria
- PDF / 991,260 Bytes
- 10 Pages / 594 x 774 pts Page_size
- 28 Downloads / 214 Views
I.
INTRODUCTION
IN the evaluation of phase diagrams and thermodynamic properties of ternary copper-metal systems, Chang, Neumann, Mikula, and Goldberg ~noted that the (3-Fe) solidus curve may be retrograde. Hansen and Anderko 2 give a nearly vertical (3-Fe) solidus curve between the two peritectic equilibria, L + (6-Fe) = (3-Fe) and L + (3-Fe) = (e-Cu). This vertical solidus curve was subsequently found experimentally by Hellawell and Hume-Rothery. 3 However, Bochvar, Ekatova, Panchenko, and Sidokhin 4 found the solubilities of Cu in (3-Fe) are much higher than those found by Hellawell and Hume-Rothery. 3 Furthermore, the solidus curve obtained by them is retrograde. Chang et al. 1 recommended the retrograde solidus curve of Bochvar et al. 4 Subsequently, Hasebe and Nishizawa 5 determined the solubilities of Cu in (3-Fe) using microprobe analysis of samples heat treated at high temperatures. The solubilities of Cu in (y-Fe) obtained by them are even greater than those of Bochvar et al. 4 but also show retrograde behavior. Most recently, Lindqvist and Uhrenius 6 redetermined the solubilities of Cu in (3-Fe) by means of a diffusion couple technique also using microprobe analysis. Their data fall in between those of Bochvar et al. 4 and Hasebe and Nishizawa. 5 It appears that the solubilities of Cu in (3-Fe) are well known. Investigators who determined other portions of the Fe-Cu phase diagram are Maddocks and Claussen, 7 Nakagawa, ~ Oelsen, Schiirmann, and Florin, 9 Tammann and Oelsen, ~~ Anderson and Kingsbury, tl Salje and Feller-Kniepmeier, tz and Speich, Gula, and Fisher. 13 On the whole, there is reasonable agreement among the results of these investigators. In their compilation, Chang et al. 1 also noted two mistakes that appear in the literature evaluations of this system, involving the conversion between wt pct and at. pct. The M e t a l s H a n d b o o k 14 contains an error concerning the peritectic equilibrium, L + (8-Fe) = (3-Fe). The analysis of the phase diagram by Hultgren, Desai, Hawkins, Gleiser, and Kelley 15 contains errors concerning the peritectic equiYING-YU CHUANG and Y. AUSTIN CHANG are, respectively, Research Associate and Professor and Chairman, Department of Metallurgical and Mineral Engineering, University of Wisconsin, Madison, WI 53706. RAINER SCHMID, Visiting Associate Professor, Department of Metallurgical and Mineral Engineering, University of Wisconsin, Madison, WI 53706, is with the Technical University Clausthal, West Germany. Manuscript submitted November 18, 1982.
METALLURGICALTRANSACTIONS A
librium, L + (y-Fe) = (e-Cu) and the eutectoid equilibrium, (3-Fe) = (e-Cu) + (cz-Fe). Extensive thermodynamic data are available for the liquid phase. Morris and Zellars, 16 Onillon, 17 Chou, 2~ and Choudary, Serkin, and Belton 21 measured the partial thermodynamic properties of copper. The data of Morris and Zellars 16 and Choudary et al. zl are extensive and in agreement. The enthalpies of mixing were determined by Woolley and Elliott, 22 Oelsen, Schfirmann, and Florin, 9 Podgornik, 23
Data Loading...
