Microstructure and properties of Mg-Li-Al alloys with Mn addition

M agnesium isone ofthe lowestdensity m aterialsand has high specific strength and rigidity and has widespread application (Fig.1).Itisaclose-packed hexagonalm etaland has poorform ability.H owever,itis wellknown thataddition of lithium to m agnesium can produce workable and body-centered cubicstructurealloys [1-5].M agnesium -lithium alloysexhibittwophasestructuresbetween 5.7 % and 10.3 % by wtLicontent,consisting ofthe α-M g (hcp)and β-Li (bcc) phases at room tem perature (Fig.2). The sin…

Microstructure and properties of Mg-Li-Al alloys with Mn addition

Mg-xLi-Al alloys with Mn addition from 0.2% to 1.5 % by wt. were produced and studied. The density of the alloys is very low, between 1.21 g/cm3 and 1.64 g/cm3, while the microstructures change from single α-, (α+β)-, to singleβ-phase with lithium content rising from 5% to 22 % by wt. The main alloy studied was LA92 alloy with Mn addition. The results of the tensile tests show that the strength decreases with increasing lithium content, while the elongation increases sharply, and the UTS and YS rise by 26.8% and 22.7% respectively, when 0.5 % by wt.Mn is added. It is also known, by microstructure observation, SEM with EDS and X-ray analysis,that adding Mn can produce some new hard phases in the alloy, which may worsen the tensile properties.