Microstructure and mechanical properties of Al-Mg-Mn alloy with erbium

The effect of trace element Er on the microstructure and properties of Al-6Mg-0.7Mn-0.1Cr-0.15Ti alloy was investigated. The results show that the ultimate room-temperature and high-temperature strength sof the alloy have not increased obviously with the addition of erbium, but the uniform elongation of alloys decreases from 9% and 27.5% to 5.5% and 22.5%, respectively. The reason is that the addition of Er will first react with Ti, Cr to form Al20Ti2Er, Al8Cr4Er phases. The precipitation strengthening makes up the weakening of grain refinement strengthening. During deformation, the primary Al(TiCr)Er and Al3Er particles fracture first and act as the microcrack sources because of the stress concentration.