Effect Of Pre-stretching Deformation And Aging On Microstructure And Mechanical Properties Of 2324 Aluminum Alloy

Al-Cu-Mg alloy is a high-strength aluminum alloy with excellent fatigue resistance,heat resistance,processing performance,welding performance,high strength,and toughness.It has been widely used in the military industry and national defense.Based on the requirements of some structural components in modern aerospace for high strength and plasticity of Al-Cu-Mg alloy,a new process combining cold rolling deformation and pre-stretching deformation was proposed in this paper.The effects of pre-deformation and aging on the microstructure and mechanical properties of 2324 aluminum alloy were systematically studied by microstructure observation and performance test analysis methods.The following important conclusions are drawn:In this study,both cold-rolled and pre-stretched deformed 2324 aluminum alloys contain T phase(Al₂₀Cu₂Mn₃),S phase(A1₂Cu Mg),and?phase(A1₂Cu).The grains of the RD-ND surface are the long axis along the tensile direction,and the grain morphology of the TD-ND surface is cloudy.There are fiber{001}<110>,Copper{112}<111>,Brass{011}<211>,S{123}<634>,Goss{011}<100>,Cube{001}<100>,and R{124}<211>texture components in the cold-rolled deformed 2324aluminum alloy.Compared to cold-rolled deformed alloy,the fiber texture component disappears in the pre-stretched deformed alloy.The intensity of Brass and S texture components are helpful to obtaining higher strength of the alloy.The maximum ultimate tensile strength and yield strength are achieved in the alloy with the pre-stretching deformation of 1.4%,enhancing 42.7 MPa and 147.8 MPa compared to the cold-rolled deformed alloy,respectively.However,the elongation is decreased to13.3%.After pre-stretching deformation,the natural aging study of 2324 aluminum alloy shows that the main precipitates of 2324 aluminum alloy are GPB zone.Furthermore,the size of the GPB zone is growing with the increase of aging time.When the natural aging time is 89 h,the strength and hardness of the alloy reach the maximum,and the ultimate tensile strength and yield strength are 511.6 MPa and 496.8 MPa,respectively.The elongation is 6.8%,and the hardness is 178.6 HV.When the natural aging time is long enough,the strength of the alloy is stable,and the ultimate tensile strength,yield strength,and elongation are around 481.3 MPa,457.6 MPa,and 6.2%,respectively.The artificial aging research on 2324 aluminum alloy after pre-stretching deformation shows that the types of precipitates are changed obviously.The metastable and stable S phases are precipitated,and the needle-like stable S phase is orthogonally distributed.After artificial aging for 6 h,the hardness of the alloy reaches the peak value of 177.7 HV;after artificial aging for 12 h,the strength reaches the best state,and the ultimate tensile strength,yield strength,and elongation reach 481.5 MPa,461.3MPa,and 7.9%,respectively.Artificial aging can accelerate the aging process and ensure the properties of the alloy.Based on the above research,the alloy natural aged for 89 h has the highest strength and hardness,but the elongation of the alloy is low.The elongation of the alloy natural aged 72 h is the highest,but the strength decreases slightly.Due to the requirements of 2324 aluminum alloy for high strength,high toughness,and high plasticity,the optimal pre-stretching deformation and aging treatment parameters of2324 aluminum alloy are finally obtained under the conditions of this study.When the pre-stretching deformation is 1.4%,natural aging is 89 h,or artificial aging is 12 h at180°C.