EFFECT OF THE ADDITION OF LI ON THE STRUCTURE AND MECHANICAL PROPERTIES OF HYPOEUTECTIC Al-Mg2Si ALLOYS

Abstract

Abstract. Alloys with various contents of Li were studied by means of differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and energy dispersive X-Ray microanalysis (EDX). The TEM investigations revealed that three different types of precipitation are formed in the alloy matrix during artificial aging. Two of the types represent different morphologies of Mg 2 Si precipitates. The appearance of the third type, identified as the δ-Al 3 Li phase, shows that the Al-Mg-Si system can be used successfully for designing an Li-containing casting alloy. However, this alloy has not yet been developed.

Multistep nucleation and multi-modification effect of Sc in hypoeutectic Al-Mg-Si alloys

“…It was reported [1, 2] that modified eutectic in Al-Si and Al-Mg 2 Si alloys (fine platelets or fibers instead coarse angular eutectic particles) can improve strength and ductility. Additions of Li, Na, Sr and transition metals (such as Cr, Sc, Ni) to Al-Si and Al-Mg-Si eutectic alloys modify the morphology of eutectic (Al-Si, Al-Mg 2 Si) from coarse angular eutectic particles (Al-Si) and eutectic lamellae (Al-Mg 2 Si) into very fine plates or fibers as well as refine the primary Al grain size [1, 2, 3, 4, 5, 6, 7]. There are two possible modification mechanisms: heterogeneous nucleation (alloying element can form heterogeneous nucleus in the system) and poisoning effect (alloying element changes a surface energy of crystallizing phases during solidification).…”

“…There are two possible modification mechanisms: heterogeneous nucleation (alloying element can form heterogeneous nucleus in the system) and poisoning effect (alloying element changes a surface energy of crystallizing phases during solidification). For the listed elements, added to the studied system, the authors currently favor the second explanation [2, 3, 6, 7]. However, in the case of Sc, both mechanisms are possible [8, 9].…”

Perancangan Struktur Road Bike Frame Menggunakan Aluminium 6063 Melalui Proses Optimalisasi Perlakuan Panas

“…Paduan aluminium-silikon yang tidak mengandung penambahan tembaga digunakan saat castability yang baik dan ketahanan korosi yang baik diperlukan. Magnesium juga dapat bertindak sebagai pengganti tembaga [6].…”