Molded articles and methods for forming molded articles are provided. For example, a molded article comprises a first region formed by a first casting material and a second region formed by mixing a molten or liquid portion of the first casting material and a second casting material. The first casting material is a molten, liquid, or fluid metal alloy, and the second casting material is a molten or fluid metal alloy. The first casting material has a different chemical composition than the second casting material. The first region and the second region are cast as one integral casting using directional solidification, and the first region and the second region have different microstructure patterns. The molded article has a lower concentration of impurities than were present in the first and second casting materials, and an interface between the first region and the second region is devoid of an oxidation layer.