Abstract
Al-Zn-Mg alloys have attracted public attention for their use in structural wrought alloys and casting alloys. They give good mechanical properties in the state of as welded or solution heat treated. Accordingly, the authors made experiments to examine whether high strength die castings can be produced from their secondary metals. In particular, the effects of small amounts of additional elements such as Ca, Zr, Th, Bi, Pb, Cu, etc. and also the effects of heat treatment on their properties were investigated.
The results obtained were summarized as follows.
(1) The addition of Ca gave their higher fluidity than any other elements. The addition of Zr improved their hot shortness and gave larger elongation percentage and higher impact value than any other elements.
(2) The addition of Pb or Bi improved their machinability, and also prevented them from adhesion to metallic mold.
(3) Form the standpoint of their good ageing properties, their mechanical properties were improved by heat treatment.
