Improved Uniformity of As-Cast Structure, Composition, and Mechanical Properties of 2524 Aluminum Alloy by Intensive Melt Shearing

The effect of intensive melt shearing (IMS) on 2524 aluminum alloy prepared by mold casting and direct chill (DC) casting was investigated. The results showed that IMS has an obvious grain refining effect on both mold casting and DC casting ingot. It is also confirmed that the coarse dendrite arms and the coarse eutectic structure at the DC ingot center almost disappeared with the application of IMS, which is one of the main reasons for the increase in the ultimate tensile strength (UTS)/elongation of the ingot center and the weak of negative centerline segregation. The increase in the number of nuclei and the reduction in the solidification time within the slurry region under the influence of IMS are considered to be responsible for the disappearance of coarse dendrite arms and coarse eutectic structure. With the application of IMS, the homogeneity of mechanical property over the ingot cross section has been improved. The difference of the UTS/elongation between the center and the edge of the ingot is reduced from 13.0 MPa/5.4% at DC without IMS to 0.9 MPa/2.5% at DC with IMS. In addition, the homogeneity of as-cast structure and composition distribution across the section of the ingot are also improved after IMS is applied. It can be concluded that IMS is an effective technique for improving the uniformity of the 2524 aluminum alloy DC ingot.