Determination of Al-2.18Mg-1.92Li Alloy’s Microstructure Degradation in Corrosive Environment

Scientific paper - Original scientific paper

• Author: Franjo Kozina
• Author: Zdenka Zovko Brodarac
• Author: Sandra Brajčinović
• Author's institution: University of Zagreb; Faculty of Metallurgy; (Department of Process Metallurgy); (Laboratory of Iron, Steel and Founding)
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy; Process Metallurgy

Abstract (english)

The utilization of aluminum-lithium-magnesium (Al-Li-Mg) alloys in the transportation
industry is enabled by excellent engineering properties. The mechanical properties and corrosion
resistance are influenced by the microstructure development comprehending the solidification of
coherent strengthening precipitates, precipitation of course and angular equilibrium phases as
well as the formation and widening of the Precipitate-free zone. The research was performed to
determine the microstructure degradation of Al-2.18Mg-1.92Li alloy in a corrosive environment using
electrochemical measurements. The solidification sequence of the Al-2.18Mg-1.92Li alloy, obtained
using Thermo–Calc software support, indicated the transformation of the Al dendritic network and
precipitation of AlLi (), Al2LiMg (T), and Al8Mg5 () phase. All of the phases are anodic with respect
to the Al enabling microstructure degradation. To achieve higher microstructure stability, the sample
was solution hardened at 520 C. However, the sample in as-cast condition showed a lower corrosion
potential (􀀀749.84 mV) and corrosion rate (17.01 mm/year) with respect to the solution-hardened
sample (􀀀752.52 mV, 51.24 mm/year). Higher microstructure degradation of the solution-hardened
sample is a consequence of phase precipitation at the grain boundaries and inside the grain of Al,
leading to intergranular corrosion and cavity formation. The phase precipitates from the Li and Mg
enriched the Al solid solution at the solution-hardening temperature.

• Keywords (english): Al-Mg-Li alloy; solidification sequence; as-cast; solution hardening; microstructure; degradation
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Crystals
• Numbering: vol. 11, pp. 2-13, 388
• p-ISSN: 2073-4352
• DOI: https://doi.org/10.3390/cryst11040338
• URN:NBN: urn:nbn:hr:115:066461
• Publication: 2022-03-27
• Document URL: https://www.mdpi.com/2073-4352/11/4/338
• Type of resource: Text
• Access conditions: Open access
• Created on: 2021-10-01 07:02:14