Zinc-base alloy for mold, zinc-base alloy block for mold and method for preparing the same

摘要

A zinc-base alloy and a zinc-base alloy block for use in the production of molds are herein disclosed, the alloy comprises 5 to 15% by weight of Al, 3 to 6% by weight of Cu and 0.01 to 0.1% by weight of Mg and the balance of Zn except for inevitable contaminants and wherein an ε -phase consisting of a Zn-Cu solid solution exists in a particulate state. The block comprises 5 to 15% by weight of Al, 3 to 6% by weight of Cu and 0.01 to 0.1% by weight of Mg and the balance of Zn except for inevitable contaminants, wherein an ε -phase consisting of a Zn-Cu solid solution exists in a particulate state and wherein it has a tensile strength as determined at 25 °C of not less than 25 kgf/mm² and a surface hardness of not less than 100 H_B. The alloy and the block can be prepared by unidirectionally solidifying a molten zinc-base alloy comprising 5 to 15% by weight of Al, 3 to 6% by weight of Cu and 0.01 to 0.1% by weight of Mg and the balance of Zn except for inevitable contaminants.