Abstract
AbstractEarlier work by the authors suggested that the formation of molten eutectic regions in Mg-Ca binary alloys caused a discrepancy in ignition temperature when different heating rates are used. This effect was observed for alloys where Ca content is greater than 1 wt%. In this work, the effect of two heating rates (25 °C/min and 45 °C/min) on the ignition resistance of Mg-3Ca is evaluated in terms of oxide growth using X-ray Photoelectron Spectroscopy. It is found that the molten eutectic regions develop a thin oxide scale of ~100 nm rich in Ca at either heating rate. The results prove that under the high heating rate, solid intermetallics are oxidized forming CaO nodules at the metal/oxide interface that eventually contribute to the formation of a thick and non-protective oxide scale in the liquid state.
Highlights
The development of ignition-resistant magnesium (Mg) alloys for cabin components of commercial planes has gained a renewed interest since their ban was lifted in an update of the SAE aerospace standard AS8049C (Gwynne, 2015) in 2014
Two different continuous heating rates were used for the interrupted tests: 25 °C/min (Low Heating Rate – LHR) and 45 °C/min (High Heating Rate – HHR)
The chemical composition of the Mg-3Ca alloy was determined by the NADCAP certified laboratory Genitest Inc via Inductively Coupled Plasma – Atomic Emission Spectrometry (ICPAES)
Summary
The development of ignition-resistant magnesium (Mg) alloys for cabin components of commercial planes has gained a renewed interest since their ban was lifted in an update of the SAE aerospace standard AS8049C (Gwynne, 2015) in 2014. The main factor driving ignition resistance, is the slowing down of Mg oxidation, which increases the surface temperature drastically and leads to Mg vaporization and ignition. An earlier study by the authors (Villegas-Armenta et al, 2020) has found that the Ti of Mg-2wt%Ca and Mg-3wt%Ca alloys were affected by heating rate, with little to no effect on pure Mg and Mg-1wt%Ca. The results showed that, unlike observations on biomass materials (Cai et al, 2018; Huang et al, 2018; Mishra & Mohanty, 2018), where a low heating rate leads to longer oxidation times and low ignition temperature, the low heating rate in binary Mg-2wt%Ca and Mg-3wt%Ca alloys leads to a high ignition temperature. Two heating rates, which exhibited very drastic differences in ignition behavior, were studied
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
