Directional solidification has been used to study effects on the structure and on materials properties from variations in the alloy contents in type AA 3003 alloys, Structure parameters such as grain size, DAS and secondary phase precipitations have been evaluated, as well as micro segregation, micro hardness and coarsening after solidification.Here the first part of the project is reported, and additions of Zn and Si have been studied. Zn additions improve the strength of the matrix of the material through solid solution hardening. At a level of 5% the hardness is improved by about 50%, but the solidification structure becomes less promising. The DAS and the secondary phases become coarse, and the solidification range increases significantly as the Zn content increases from 2.5 to 5%.Additions of Si, which have a significantly lower solubility than Zn, quickly gives larger amounts of secondary phase precipitations and a longer solidification interval.Directional Solidification of Type AA3003 Alloys with Additions of Zn and Si.