Containing Scandium, Zirconium 2524 Aluminum Alloy Performance

2524 Aluminum alloy with minor Sc and Zr was designed and its ingots were prepared by semi-continuous casting.The evolution rules of the microstructures and properties of 2524+(Sc+Zr)Aluminum alloy at different heat-treatment conditions were studied by using hardness and electric conductivity measurement,room temperature tensile test,optical microscopy (OM),X-ray diffraction(XRD)and electronic microscopy analysis(SEM, TEM).And the heat-treatment regimes were optimized.The results were analyzed and discussed theoretically.Several conclusions can be summarized as follows:1.There are three results during ingot homogenization:firstly,when homogenization temperature lower than 400℃,the matrixes decompose and precipitateθand S,but higher than 400℃,the educts dissolve to the matrix;secondly,Sc and Zr supersaturated solid solution decompose and precipitate Al₃(Sc,Zr)particles which possess high thermal stability;thirdly, the coarse interdendritic phases dissolve gradually,and the dendritic structure eliminate at 490℃.2.The best homogenization treatment of 2524+(Sc+Zr)Aluminum alloy is to pre-heat at 420℃for 8h,then to heat at 490℃for 16h,to cool in air. Which is beneficial for the precipitation of Al₃(Sc,Zr)particles.3.The best solution treatment of 2524+(Sc+Zr)Aluminum alloy is to heat at 498℃for 20min,then to quench in water.After solutionizing and natural aging for 96h,the room temperature tensile properties(L)σ_b,σ_0.2andδof plates are 464MPa,303MPa and 25%respectively.4.The equiaxed grains of 2524+(Sc+Zr)-T4 sheet have no orientation,so the tensile properties also have no orientation.The room tensile properties(T) areσ_b=457 MPa,σ_0.2=303 MPa andδ=26%,which reaches the target of the study.When the fatigue life equals to 10⁷,the stress stand is 194MPa.