Recycling of Magnesium Alloys

Effects of ultrasonic treatment on microstructure and tensile strength of AZ91 magnesium alloy

“…5, 9 and 10 also show the effect of UST on size, sphericity and sphericity distribution of MnFeAl(Si) particles, which form at about 650 • C [22], and reveal that similar to the previous phase, the average size of MnFeAl(Si) particles decreases and their sphericity increases by increasing the applied UST power. Of course, since MnFeAl(Si) particles are intrinsically round, the effect of UST on the sphericity of this phase is not as significant as on that of previous phases.…”

“…Mg 2 Si is formed at about 637 • C in alloys containing less than 0.5%Si [23] and the formation temperature of MnFeAl(Si) is about 650 • C [22]. Therefore, both of these phases are formed at temperatures less than but relatively close to the UST temperature.…”

“…Considering the chemical composition of the alloy, the other two intermetallic phases are by far less abundant than Mg 17 Al 12 , but still present in detectable quantities. It is somewhat surprising that while the occurrence of MnFeAl(Si) in AZ91 alloy has been widely reported [1,22], iron limits for AZ91 alloy are not indicated in many references [28], and consequently at least some optical emission spectrometry systems are not programmed to record iron concentration in the alloy. As a result, while Table 1 does not show the iron content of the alloy, EDS analyses prove the existence of MnFeAl(Si) phase in the microstructures.…”

“…For aluminium and silicon containing magnesium alloys, these phases may include Mg 2 Si, MnFeAl(Si) and Mg 17 Al 12 phases [22,23].…”

Effect of heavy metal impurities in secondary Mg alloys on the microstructure and mechanical properties during deformation

“…However, the production of magnesium metal from the raw material requires a considerable amount of primary energy, which must be considered in the overall energy balance to properly estimate the environmental benefits of using Mg alloys in transportation [1,2]. Considering that a significant amount of the metal used for the production of die cast components ends up as scrap, and that the secondary production of magnesium requires only 5% of the energy required to manufacture the primary metal [3], the use of recycled magnesium would potentially yield important environmental and economic benefits. The European guideline on used cars (End of Life Vehicles Directive) sets clear quantified targets for reuse, recycling and recovery of vehicles and their components.…”