Aluminum is a non-ferrous metal that is widely used in everyday life, both on a large and small industrial scale as well as a household scale. In this research, used diesel motor piston material for casting screw. The addition of 0.1%, 0.3% Titanium Boron (Ti-B) and 0.1%, 0.3% Magnesium (Mg) for screw making by casting is expected to improve the physical and mechanical properties of the material. Tests carried out in this research are to wear testing and microstructure. The analysis of the results of this wear test shows that the aluminum alloy for making screws with the addition of 0.1% Titanium-Boron (TiB) and 0.1% Magnesium (Mg) has a better wear resistance, which is 1.154 mm² / kg compared to the addition of the element 0.3% Titanium-Boron (TiB) and 0.3% Magnesium (Mg) and without the addition of any elements which have wear resistance values of 1.252 mm² / kg and 1.596 mm² / kg, respectively. Microstructure testing shows the grain structure in aluminum alloy from casting results with the addition of Ti-B and Mg elements getting smaller and denser. This proves that the more elements of Ti-B and Mg added to the casting of aluminum alloys, the smaller the structure of the grain will be and will affect the mechanical properties of the screw.