Recycling-Oriented Design of the Al-Zn-Mg-Ca Alloys

Abstract

Approaches to the design of recycling-tolerant Al-Zn-Mg alloys were formulated to be achieved via combined Ca, Fe, and Si, and appropriate solidification conditions and heat treatment. A CalPhaD calculation and experimental study were employed for analysis of the Al-8%Zn-3%Mg alloy doped with 1–2%Ca, 0.5%Fe, and 0.5%Si. The Al-8%Zn-3%Mg-1%Ca-0.5%Fe-0.5%Si (AlZnMg1CaFeSi) alloy was preliminarily found to be promising since it showed a high equilibrium solidus, and an as-cast structure including curved phases (Al), Al3Fe, Al2CaSi2, Al10CaFe2, and (Al, Zn)4Ca; favouring a further spheroidization response during a two-step annealing at 450 °C, 3 h + 520 °C, 3 h. Furthermore, the alloy showed an excellent age-hardening response (195 HV, T6), which did not yield the values of the base alloy and outperformed the values of the other experimental counterparts. Regarding feasibility, 80% reduction hot rolling was successfully conducted, as well as a brief comparison with commercial 6063 impurity-tolerant alloys. As it showed qualitatively similar structural patterns and Fe and Si alloying opportunities, the AlZnMg1CaFeSi alloy may serve as a sustainable basis for the further development of high-strength aluminum alloys tailored for manufacture from scrap materials.

Impact of Remelting on ZnAl4Cu3 Alloy with Addition of Cd on Selected Technological and Mechanical Properties

“…Fluidity values compared to the Cd-free alloy increased by 22.4% from 647 to 792 mm. The reason for this increase is the cadmium's effect on chemical composition and microstructure, as well as on physical properties, in particular, specific heat (232 J kg −1 K −1 ) and latent heat (57.103 J kg −1 ) [1]. By altering the chemical composition of the alloy, a new phase arose, and it had significant influence on the properties of the alloy.…”

“…That is why a large amount of scrap is created during the production of small castings. The role of recycling in the metallurgical sector has always been crucial and predominant and has had a major impact not only on the global economy and energy consumption, but also on the ecological environment and human life [1].…”