Study On The Structure And Defects Of 2524 Aluminum Alloy Ingot Under The Condition Of Intensive Melt Shearing

The microstructure and defects of aluminum alloy has been an important part of aluminum alloy ingot quality.Improve macro and micro morphology of ingot,reduce segregation and oxide film and the grain size are of great significance for improving the quality of aluminum alloy ingot and performance of subsequent products.The main purpose of this study is to apply intensive melt shearing to aluminum alloy melt,and study the effect of intensive melt shearing on structure and defects of 2524 aluminum alloy ingot.The main contents of this paper are as follows:(1)The influence of intensive melt shearing on porosity,oxide film and macro segregation in 2524 aluminum alloy;(2)The influence of intensive melt shearing on the structure,the second dendritic arm spacing and the grain size of 2524 aluminum alloy ingot.The results show that:(1)The intensive melt shearing can effectively reduce the porosity of 2524 aluminum alloy ingot.When the melt is sheared for 180 seconds at 700 degree Celsius,the number of defects in the ingot after macro corrosion is the least,and the size is the lowest;(2)The distribution of Cu and Mg at the center of the 2524 aluminum alloy ingot is more uniform along the thickness of the ingot with the increase of the intensive melt shearing temperature(625?-700?)and the prolongation of the intensive melt shearing time(30s-180s).Typically,When the melt is sheared for 1 80 seconds at 700 degree Celsius,the Cu and Mg elements at the center of ingot center distribute most evenly;(3)The number and size of the oxide film in the 2524 aluminum alloy ingot(without refinement)without intensive melt shearing are large,while the internal oxide films are almost completely broken after applying intensive melt shearing,and the oxide film inside mainly include aluminum oxide(Al2O3),a small amount of nonmetallic inclusion MgAl2O4(MgO.Al2O3),and C inclusions;(4)After intensive melt shearing,the second dendritic arm spacing at the center of 2524 aluminum alloy ingot significantly reduced,and become more uniform.Without intensive melt shearing,the second dendritic arm spacing is 49 micron,while it is 28 micron after intensive melt shearing.(5)The intensive melt shearing can effectively refine the central grain size of the ingot.With the increase of strong intensive shearing temperature(650?-700?),the grain size at the center of 2524 aluminum alloy ingot(with and without refinement)is refiner,it can be reduced from 133?m,205?m to 107?m,128?m,reduced by 20%and 37.5%,respectively.In addition,with the prolongation of strong intensive shearing time(30s-180s),the grain size at the center of 2524 aluminum alloy ingot(with and without refinement)is refiner,too,it can be reduced from 215?m to 108?m.