Innovative family of AlMg(X)Si(Y)Mn casting alloys for industrial applications

DOI: 10.62564/M4-IV2214

Nick Iefimov, Konstantin Grinkevych, Igor Voskoboynik

Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


The choice of the innovative family of AlMg(X)Si(Y)Mn for the development of high-strength aluminum foundry alloys with increased fluidity has several justified reasons. The wide regions of univariant eutectic transformation in innovative family of AlMg(X)Si(Y)Mn casting alloys allow for flexible variation of alloy component ratios while maintaining their phase composition [1]. The structure of alloys in this system morphologically resembles modern foundry alloys, and the nature of phase equilibria allows for a significant increase in magnesium content in the solid solution compared to traditional foundry alloys. Thus, materials can be created that simultaneously utilize all strengthening mechanisms (composite, solid solution, and dispersion). Considering the peculiarities of the topology of the phase diagram of innovative family of AlMg(X)Si(Y)Mn casting alloys contributed to the creation of a new high-strength (σB up to 450-500 MPa) aluminum-based casting alloy. In this alloy, the matrix is a solid aluminum solution strengthened by Mn and Cu-containing phases that do not interact with the eutectic and are precipitated during thermal treatment. The influence of natural aging on the hardness of Mn and Cu alloyed alloys has been investigated. An increase in the saturation of the solid solution during alloying or an increase in quenching temperature accelerates the processes of forming precipitates that strengthen the matrix, thus the increase in hardness in the first 48 hours after quenching depends on the temperature and composition of the alloys. Subsequent artificial aging proceeds through altered stage decomposition, increasing the hardness of the alloys and, consequently, reducing their ductility and fracture toughness. A heat treatment regimen was developed, including quenching and subsequent two-stage aging.

Keywords
aluminum, hardness, plasticity characteristic

Acknowledgments
This work was partially supported by the Frantsevich Institute for Problems in Materials Science, NAS of Ukraine (“Innovative family of AlMg6Si2Mn casting alloys for transportation applications”).

References
[1] Legka, T. M., Mika, T., Milman, Y., Korzhova, N. P., Voskoboynik, I. V., and Mordovets, N. M. (2019). Constitution of the Al Corner in the Ternary Al–Ge–Mg Phase Diagram. Powder Metallurgy and Metal Ceramics, 57(11–12), 716–722.