Flammability of Mg–X Binary Alloys

Abstract

This research builds on our prior studies on Mg flammability. [1,2] Magnesium (Mg) alloys have a low density, good damping characteristics, good machinability, and a good strength to weight ratio. However, Mg is inherently reactive so that Mg alloys are prone to oxidation. They have moderate corrosion resistance [3][4][5][6] and Mg alloys require a cover gas during melting. [7] Significant research has been carried out on protecting Mg alloys during melting. [2] There has however been limited work done to study Mg alloys directly exposed to a flame. [8][9][10] Our previous work [2] studied the influence of Al and Y on the flammability of Mg alloys. One end of a cylindrical specimen was exposed to a free diffusion, liquid petroleum gas (LPG) flame. There were important differences in the ignition characteristic for HP Mg, AZ61, and AZ91 of (i) the cylindrical Mg specimens subjected to direct LPG flame impingement on the specimen tip, and (ii) a hot detached blob of molten metal detached from the specimen tip. The cylindrical specimen tip required direct continued exposure of the LPG flame to ignite, and extinguished once the LPG flame was withdrawn. Ignition required at least partial melting. The hot detached un-ignited molten blob, detached from the specimen tip, ignited readily even without the exposure to the LPG flame. Burning was COMMUNICATION

Oxidation of magnesium alloys at elevated temperatures in air: A review

“…5: (a) specimen melted and a minor ignition occurred at the end of the specimen; (b) the incipient ignition was extinguished readily even in the presence of the LPG flame. Reproduced from Prasad [59] with permission from Elsevier. Figure 21: The influence of the Be content on weight change kinetics of AZ91D in argon.…”

“…Prasad et al [58,59] found that there was no burning before melting in their study of the flammability of a range of Mg-X binary alloys (X = Al, Ca, Si, Sn, Sr, La, Mn, Zn, Zr, Ce, Gd, and Nd), AZ61 and AZ91, using a flame test as illustrated in Fig. 5 6 shows a typical test for AZ61.…”

“…Prasad et al [59] studied the flammability of a series of Mg-Y binary alloys through flame test as illustrated in Fig. 5.…”

Review of Recent Developments in the Field of Magnesium Corrosion

“…Thereupon there was burning and typically enough heat was generated to melt a blob of Mg, which dropped to the sand covered furnace floor and continued to burn until consumed. In contrast, the Mg specimen extinguished when the flame was withdrawn, after …”

“…This showed a flame temperature of 1100 °C with a reproducibility of ± 10 °C. There were thermocouples in the specimen, that allowed evaluation of the temperature at the end of the Mg specimen, after …”