| 2024 aluminum alloy is widely used in aircraft skin manufacturing.It has important theoretical value and practical significance to study its mechanical properties and corrosion resistance.In this paper,the effects of different rolling and heat treatment processes on the microstructure and properties of 2024 aluminum alloy were studied.The microstructure,mechanical properties and intergranular corrosion evolution principle of the alloy under different rolling and heat treatment processes were analyzed by means of optical microscope(OM),electron microscope(SEM,TEM),X-ray diffraction(XRD)analysis,differential scanning calorimetry(DSC),electron backscatter diffraction(EBSD)and electrochemical methods.The main research results of this experiment are as follows :(1)As the solution temperature increase from 438℃ to 528℃,the hardness,strength and elongation of the 2024-T6 aluminum alloy increase first and then decrease after aging at 180℃/14 h.When the solution temperature is498°C,the S phase is dispersed and the mechanical properties and corrosion resistance of the alloy are the best;(2)When the quench rate decrease,Cu and Mg atoms gather at dislocations and grain boundaries,which lead to the transformation of intergranular corrosion morphology of 2024-T3 aluminum alloy from pitting to grid,the density of intragranular S phase in 2024-T6 aluminum alloy decrease,and the size of intergranular S phase increases,resulting in the significant decrease of the mechanical properties and corrosion resistance of the alloy;(3)With the increase of aging time,the potential difference between the GPB zone in the 2024-T4 alloy and its surrounding matrix increases,and the depth of intergranular corrosion increases.With the increase of artificial aging time,the size and spacing of intergranular S phases increase.Compared with under-aging and over-aging,the comprehensive properties of 2024-T6 aluminum alloy reach the best;(4)When the solid solution temperature is 498℃,quench transfer time and quench medium temperature are 2 s and 20℃,the mechanical properties and corrosion resistance of 2024-T6 aluminum alloy are the best.The hardness is 155 HV,the yield strength and tensile strength are 375 MPa and500 MPa respectively,the elongation is 25.49%,and the intergranular corrosion depth is 138.65 μm;(5)When the final rolling temperature is low(207℃),the average grain size and average Schmid factor of 2024-T4 aluminum alloy are small,and the strength is high,and the yield strength and tensile strength are 306 MPa and 487 MPa respectively;when the final rolling temperature is high(280℃),the proportion of low angle grain boundary and {111} plane texture of 2024-T4 aluminum alloy is high,the texture content with large Schmid factor is small,and the corrosion resistance is excellent.The maximum intergranular corrosion depth is 73.88 μm. |
PDF Full Text Request