Thermodynamic and Structural Study of the Copper-Aluminum System by the Electrochemical Method Using a Copper-Selective
- PDF / 1,892,850 Bytes
- 14 Pages / 593.972 x 792 pts Page_size
- 16 Downloads / 157 Views
THE copper-aluminum binary system remains industrially critical due to the prevalence of copper as an alloying agent for aluminum and a base metal for aluminum bronze products. In the aluminum industry, the addition of copper enables precipitation hardening and heat treatment[1] in 2XXX series alloys, and increases strength in 2XXX and 6XXX alloys.[2] Conversely, aluminum bronzes have long been utilized for corrosion-resistant applications,[3] and remain an active area of research for high-strength and wear-resistant alloys.[4] All of those products are processed via the molten state, and require a careful mastering of the concentration and distribution of copper in both the liquid state and during solidification. Examples of the corresponding processing issues include macrosegregation[5] or control of the copper content when using recycled feeds.[6,7]
CASPAR STINN is with the Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 and also with the Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139. ANTOINE ALLANORE is with the Department of Materials Science and Engineering, Massachusetts Institute of Technology. Contact e-mail: [email protected] Manuscript submitted April 8, 2018.
METALLURGICAL AND MATERIALS TRANSACTIONS B
Indeed, despite the prevalence of copper-aluminum alloys in industrial applications, liquid phase phenomena remain uncertain starting from inconsistencies in models for copper-aluminum thermodynamics[8–14] and melt structure.[15–18] In addition, while physical properties such as density, viscosity, and surface tension of copper-aluminum melts have received experimental attention,[13,19–22] such quantities are difficult to measure accurately for molten aluminum alloys,[19] and limited effort is found to relate these properties to accurate experimental thermodynamics of mixing data. While molecular dynamics simulations[15–18,23–26] have attempted to elucidate the relation between thermodynamic, structural, and physical properties for the copper-aluminum system, the efficacy of available computational approaches is hindered by a lack of experimental data for comparison. An electrochemical study of the copper-aluminum system is herein investigated, with the objective to inform the free energy and entropic thermodynamics of mixing of the liquid binary system. Consequently, thermodynamics of mixing properties are used to inform the structural and transport properties of the melt. To study the thermodynamic behavior of the copper-aluminum system, the use of a copper-selective, alumina-based solid electrolyte is proposed. Beta (b) and beta¢¢ (b¢¢) alumina solid electrolytes (BASE) have been extensively investigated for use in high-temperature electrochemical applications due to their thermal stability, low electronic conductivity, and high and selective ionic conductivity. Most BASE studies and applications thus far have targeted sodium and lithium ion
conducting solid electrolytes, with far less attention gi
Data Loading...