Research On Microstructure Transformation And Microscopic Mechanism Of 2324 Aluminum Alloy Based On Optimization Of Heat Treatment Process In Sheet Forming Process

2324 aluminum alloy has more excellent properties than 2024 aluminum alloy,but 2324aluminum alloy is a new type of aluminum alloy,and the heat treatment process is not perfect.And through the study of orthogonal experiments,data and theoretical support are provided for the rapid exploration of heat treatment methods for new alloys in the future.First,the homogenization treatment of as-cast 2324 aluminum alloy was studied.Through XRD,SEM and Jmat Pro phase diagram simulation,it was found that the mechanical properties of the alloy decreased with the increase of Fe and Si content in the alloy.In order to obtain a supersaturated solid solution,the air transferred The time needs to be less than 5.67 s.There is dendrite segregation in the as-cast structure,and Cu and Mg elements are distributed periodically along the dendrite.During the homogenization process,the dendrite segregation in the as-cast structure gradually disappeared,and the diffusion of Mg element was faster than that of Cu element.Finally,the precipitation phase and kinetic calculation were observed by XRD and SEM,and it was concluded that 490°C for 20 h was the best homogenization parameter.Next,the effects of solid solution and aging on the mechanical properties of the alloy were studied.Both traditional experiments and orthogonal experiments showed that the optimal heat treatment parameters of the alloy were 500°C for 140 min and 190°C for 4 h.Tensile strength,yield strength and hardness all rise first and then decrease,and go through three processes:under-aging,peak aging,and over-aging.The higher the aging temperature,the faster the time to reach the peak aging,and the shorter the duration of the peak aging..The peak performance first increased and then decreased with the aging temperature,and the peak appeared at 190°C.The elongation after fracture first decreases and then becomes smooth with the prolongation of time.With the increase of the aging temperature,the elongation after fracture decreases faster,but the final stable stage is basically the same.According to the orthogonal test,the order of influence on _b?is Taging>Tsolid solution>taging>tsolid solution,the order of influence on?_0.2 is Taging>t_{solid solution}>Tsolid solution>taging,and the order of influence on?is T_aging>t_{solid solution}>T_solidsolution>taging,the order of influence on hardness is Taging>tsolid solution>taging>Tsolid solution.Aging temperature has a significant effect on all factors.Finally,the precipitation phase after aging is studied,and it is found that with the prolongation of aging time,the precipitation sequence of the alloy is:α-Al→GPB region→S’phase→S phase.In the 2324 aluminum alloy,the phase relationship between the S phase and the aluminum matrix is<100>_Al//<100>_S There are two variants.The T phase is coherent with the matrix,and the size of the T phase is between 100 nm and 500 nm.There is a stress field around the S phase.These stress fields are caused by the mismatch between the S phase and the collective and the aggregation of alloy elements around the S phase.The smaller the S phase,the greater the surrounding stress field and the farther away from the S phase.,the smaller the stress field.The activation energy of the S’phase decreases with the increase of the transition fraction,and the activation energy of the S phase increases with the increase of the transition fraction.