Effect of the Modified Ablation Casting Process on the Mechanical Properties and Microstructure of Near Eutectic Ai-Si Alloy

A novel version of the well-known ablation casting process named as the direct water spraying (DWS) was introduced by applying the process on a simple geometry solidifying casting with a near eutectic A413.0 aluminum alloy. The new solidification term named total cooling rate was found more efficient in justification of the improvement in mechanical properties. A comparison between the DWS processed casting and the conventionally sand-cast counterpart revealed that the secondary dendrite arm spacing could decrease from conventional 68 μm to 32 μm in the DWS specimens. The size of other microstructural features such as eutectic micro-constituents, iron-bearing phases, and shrinkage porosities experiences a significant drop caused by the DWS process. All these were attributed to the higher cooling rate induced by efficient heat extraction. The average ultimate tensile strength and elongation increased from the conventional values of 146 MPa and 2.2% to 160 MPa and 5.2% in DWS, respectively.