Effect Of CeLa And Ce Microalloying On The Microstructures And Properties Of Al-Cu-Mn-Mg-Fe Alloys

Lithium ion batteries have been widely used with the rapid development of new energy vehicles and portable devices.As an important part of square aluminum shell lithium battery,shell material has received much attention.Due to low strength,traditional Al alloy shell materials cannot satisfy the future lightweight requirement of lithium battery shell alloy.In this thesis,we developed several Al-Cu-Mn-Mg-Fe alloys as lithium battery shell material.We improved the mechanical properties and corrosion performance of the alloy by adding the rare earth Ce or CeLa.The microstructures,mechanical properties and corrosion properties of Al-Cu-Mn-Mg-Fe alloys with different Ce or CeLa addition were investigated and the main experimental results are as follows:?1?For the Al-Cu-Mn-Mg-Fe alloys treated with low-temperature annealing,the main phases were S?Al₂CuMg?phase,T(Al₂₀Cu₂Mn₃)phase,Al₆?Mn,Fe?phase and Al₇Cu₂Fe phase.New phase of AlCuCe?La??Al₈Cu₄Ce and Al₆Cu₆La?could be found due to CeLa addition.AlCuCe?La?phase tended to form at the surface of Al₆?Mn,Fe?particles.Thus the Al₆?Mn,Fe?phase could be effectively refined.The number density of T phase firstly increased and then decreased with the increase of CeLa addition.The electrical conductivity decreased with increase of the CeLa addition.The Goss texture was the major texture for the CeLa-free alloy,while the rolling texture component Brass was the main texture for the CeLa-containing alloys.Ce microalloying resulted in the formation of Al₈Cu₄Ce phases.Al₈Cu₄Ce phases had a significant refining effect on the Al₆?Mn,Fe?phase.After room-temperature aging and low-temperature annealing process,very fine S?phases formed in the Ce-containing alloy rather than in the Ce-free alloy.?2?Ce or CeLa microalloying could improve the tensile strength and elongation of Al-Cu-Mn-Mg-Fe alloys.Particularly,Ce or CeLa microalloy-ing had an obvious effect to improve the high-temperature tensile properties of the alloy.The optimal addition of Ce to improve mechanical properties of Al-Cu-Mn-Mg-Fe alloy was 0.25%.The optimal addition of CeLa to improve mechanical properties of Al-Cu-Mn-Mg-Fe alloys was 0.25%when the testing temperature was below 200?,while the optimal value was 0.50%when the testing temperature was higher than 200?.The tensile strength and elongation of Al-Cu-Mn-Mg-Fe alloys could be greatly improved by using the room-temperature aging process before low-temperature annealing.Compared to CeLa,Ce microalloying was beneficial to the improvement of the tensile properties of the Al-Cu-Mn-Mg-Fe alloy.?3?Ce or CeLa microalloying could improve the corrosion performance of the Al-Cu-Mn-Mg-Fe alloys.The corrosion resistance of the alloy decreased with the increase of Cl^-concentration.The corrosion resistance of Al-Cu-Mn-Mg-Fe alloy could be greatly improved by using the room-temperature aging process before low temperature annealing.The optimal addition of Ce or CeLa to improve corrosion resistance of the Al-Cu-Mn-Mg-Fe alloys was 0.25%.Compared to Ce,CeLa microalloying was beneficial to the improvement of the corrosion resistance of the Al-Cu-Mn-Mg-Fe alloys.