Cu-Hf (Copper-Hafnium)
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upplemental Literature Review: Section III
Cu-Hf (Copper-Hafnium) H. Okamoto
The Cu-Hf phase diagram in [Massalski2] was redrawn from [1988Sub]. However, [1991Oka] pointed out that the thermodynamic model adopted by [1988Sub] did not result in the phase diagram as shown by them. Apparently, as the assessed phase diagram, [1994Sub] accepted the CuHf phase diagram that was calculated by [1991Oka] using thermodynamic parameters given by [1988Sub], although [1991Oka] is not quoted. According to [1991Oka], the thermodynamic parameters used by [1988Sub] were very unlikely because the calculated phase diagram included many unlikely features, e.g., only one phase is stable at room temperature. Figure 1 shows the Cu-Hf phase diagram calculated by [2006Lia]. Problems in the thermodynamic model [1988Sub] and the phase diagram [1994Sub] were solved. Figure 2 is an enlargement of Fig. 1 on the Cu-rich end. More recently, [2006Woo] concluded that Cu10Hf7 melts peritectically at 1025 °C, not congruently, by a reaction L + CuHf2 = Cu10Hf7 based on thermal analysis, scanning electron microscopy, and X-ray microanalysis.
Accordingly, the thermodynamic model may require further refinement.
References 1988Sub: P.R. Subramanian and D.E. Laughlin, The Cu-Hf (Copper-Hafnium) System, Bull. Alloy Phase Diagrams, 1988, 9(1), p 51-56 1991Oka: H. Okamoto, Reevaluation of Thermodynamic Models for Phase Diagram Evaluation, J. Phase Equilibria, 1991, 12(6), p 623-643 1994Sub: P.R. Subramanian and D.E. Laughlin, Cu-Hf (CopperHafnium), Phase Diagrams of Binary Copper Alloys, P.R. Subramanian and D.E. Laughlin, Eds., ASM International, Materials Park, OH, 1994, p 200-204 2006Lia: D. Liang and Y. Liu, Reevaluation of the Cu-Hf Binary System, J. Alloys Compd., 2006, 426, p 101-105 2006Woo: R.H. Woodman, B.R. Klotz, and L.J. Kecskes, Observation of Incongrument Melting in Cu10Hf7, J. Phase Equil. Diffusion, 2007, 27(5), p 477-481
Weight Percent Hafnium 0 10 20 30
40
50
60
70
80
90
100 2231°C
2200 2000 1800
(βHf )
L
1600
1541°C
1400
1311°C
1200 1084.87 1000 963
13.8
99.7
1115°C 1054 991°C
0.3 7.5
800
1283°C 72.9
33.2 985°C 961°C 35.7 43.6
980°C
(αHf )
CuHf2
400
Cu8Hf3
Cu5Hf
600
Cu10Hf7
(Cu)
Cu51Hf14
Temperature,°C
78.9
1743°C 96 99.6
200 0
10
Cu
20
30
40
50
60
70
80
Atomic Percent Hafnium
90
100
Hf
Fig. 1 Cu-Hf phase diagram
Journal of Phase Equilibria and Diffusion Vol. 28 No. 6 2007
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Section III: Supplemental Literature Review Weight Percent Hafnium 0
2
4
6
10
8
12
14
18
16
20
1200
L
1100 1084.87 1000
963°C 0.3
7.5
900
Temperature, °C
22
L +Cu5Hf (Cu)
800
700
(Cu) +Cu5Hf 600
500
400
300 0
1
2
Cu
3
4
5
6
7
8
9
Atomic Percent Hafnium
Fig. 2 Cu-rich end of the Cu-Hf phase diagram
584
Journal of Phase Equilibria and Diffusion Vol. 28 No. 6 2007
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