Abstract
A many excellent Al-alloys are known in these days but a quite good castable Al-alloys which show high mechanical properties are very rare. The author has studied on the solidifying volume change of Al and its alloys and found the effective property of titanium in these regions. Titanium is aused in some Al-alloys with a view to make a fine crystallization but is not utilized as the element which reduces the solidifying shrinkage of Aluminium remarkably. Then, the composition of Al-multiple system containing titanium has been studied by measuring the castability, the mechanical, the physical and the chemical properties and a new composition of castable and strong Al-alloy has been decided. This composition is as follows: Si 3.5%, Cu 2%, Mg 0.4%, Mn 0.5∼2%, Ti 0.4%, Al residue.
