Effect of ageing process on microstructure and properties of 2124 aluminum alloy thick plate

Mechanical properties of 2124 aluminum alloy thick plate in short-transverse direction were investigated when ageing at 170-180℃ for different time by room temperature tensile test.The microstructure morphology of alloy after different ageing processes was studied by TEM and SEM.The results show that the suitable ageing process of 2124 aluminum alloy plates is 175℃ for 10h.Yield strength, tensile strength and elongation are 372,422MPa and 2.9%, respectively.The main precipit-ation is S' phase, and also a small quantity of GPB zone and coarse T phase exist at this moment.Ageing temperature is the main factor affecting the density and size of the alloy precipitation.The higher the ageing temperature is, the quicker the rising of strength, the shorter time to reach the maximum strength.The increasing strength difference between the matrix and grain boundary is the main cause for the decrease of the elongation.