Liquidus and Solidus Calculations

For many noble metal products casting is an important part of the production route and some noble metal alloys are even used as solder alloys. For noble metal alloys in other applications it may be of importance to make sure that the designed alloy do not melt at a certain temperature. There are many reasons why it is important to be able to predict the liquidus and solidus temperature as a function of composition for an alloy. Below are two diagrams showing a comparison between calculated and experimental liquidus and solidus temperatures for a large number of commercial noble metal alloys.

Ag-Cu-Ge

The addition of Ge to Ag-Cu alloys is known to increase both the corrosion resistance and the mechanical properties of the alloy. Due to this the Ag-Cu-Ge ternary system is interesting both for Ag-based solder alloys, but also for sterling silver alloys used for jewelry. The possibility to calculate melting temperature and solidification sequence for alloys in this ternary system is thus important. One example is the calculated liquidus surface projection that shows which solid phase first forms during solidification. Below is the calculated liquidus surface projection for the Ag-Cu-Ge system compared with experimental data [2009Nag; 2015Akh; 2017Guo].

References

[2009Nag] E. Nagels, J. Van Humbeeck, L. Froyen, The Ag–Cu–Ge ternary phase diagram. J. Alloys Compd. 482, 482–486 (2009).

[2015Akh] A. M. Akhmetova, A. T. Dinsdale, A. V Khvan, V. V Cheverikin, A. V Kondratyev, D. O. Ivanov, Experimental investigations of the Ag–Cu–Ge system. J. Alloys Compd. 630, 84–93 (2015).

[2017Guo] C. Guo, L. Zou, C. Li, Z. Du, Experimental Investigation and Thermodynamic Modeling of the Ag-Cu-Ge System. Metall. Mater. Trans. A. 48, 4965–4976 (2017).