Dies for die casting aluminum and other metals

1. A tool for contacting a molten metal at elevated temperature, wherein the tool is made from an underaged Ni—Be alloy containing about 1.0 to less than 3.0 wt. % Be.

2. The tool of claim 1 , wherein the tool is a mold or mold insert.

3. The tool of claim 2 , wherein the Ni—Be alloy has a thermal conductivity of at least about 20 Btu/ft.hr.F.

4. The tool of claim 2 , wherein the Ni—Be alloy has a thermal conductivity of at least about 25 Btu/ft.hr.° F.

5. The tool of claim 4 , wherein the hardness of the Ni—Be alloy is 90% or less of its peak aged hardness.

6. The tool of claim 5 , wherein the hardness of the Ni—Be alloy is 75% or less of its peak aged hardness.

7. The tool of claim 4 , wherein the Ni—Be alloy contains at least one additive selected from the group consisting of Al, C, Co, Cr, Cu, Fe, Mg, Mo, Ti, Y and the Rare Earth Elements.

8. The tool of claim 4 , wherein the alloy contains about 1.0 to 2.0 wt. % Be.

9. A tool for contacting a molten metal at elevated temperature, wherein the tool is made from an underaged Ni—Be alloy, the amount of Be in the Ni—Be alloy being sufficient Be so that a continuous coating of beryllium oxide forms on the surfaces of the tool but not so great that the alloy becomes brittle.

10. A tool for contacting a molten metal at elevated temperature, wherein the tool is made from an underaged Ni—Be alloy containing about 1.0 to less than 3.0 wt. % Be, at least one surface of the tool having a tightly adherent beryllium oxide coating sufficient to substantially prevent aluminum soldering when the surface is contacted with molten aluminum.

11. The tool of claim 10 , wherein the hardness of the Ni—Be alloy is 90% or less of its peak aged hardness.

12. The tool of claim 11 , wherein the hardness of the Ni—Be alloy is 75% or less of its peak aged hardness.

13. The tool of claim 10 , wherein the Ni—Be alloy contains at least one additive selected from the group consisting of Al, C, Co, Cr, Cu, Fe, Mg, Mo, Ti, Y and the Rare Earth Elements.

14. The tool of claim 10 , wherein the alloy contains about 1.0 to 2.0 wt. % Be.

15. A process for solidification of a molten metal selected from aluminum, aluminum alloy, magnesium, magnesium alloy, copper, copper alloy, zinc and zinc alloy comprising charging the molten metal into a die, the die optionally having a die insert, and allowing the molten metal to solidify therein, wherein the die or die insert or both are made from an underaged Ni—Be alloy containing about 1.0 to less than 3.0 wt. % Be.

16. The process of claim 15 , wherein the Ni—Be alloy contains about 1.0 to 2.0 wt. % Be.

17. The process of claim 15 , wherein the hardness of the Ni—Be alloy is 90% or less of its peak aged hardness.

18. The process of claim 17 , wherein the hardness of the Ni—Be alloy is 75% or less of its peak aged hardness.

19. The process of claim 15 , wherein the Ni—Be alloy contains at least one additive selected from the group consisting of Al, C, Co, Cr, Cu, Fe, Mg, Mo, Ti, Y and the Rare Earth Elements.

20. A mold or mold insert for contacting a molten metal at elevated temperature, wherein the mold or mold insert is made from an underaged Ni—Be alloy, the amount of Be in the Ni—Be alloy being sufficient Be so that a continuous coating of beryllium oxide will form on the surfaces of the tool when contacted with molten aluminum but not so great that the alloy becomes brittle.

21. The mold or mold insert of claim 20 , wherein the alloy contains about 1.0 to less than 3.0 wt. % Be.

22. The mold or mold insert of claim 21 , wherein the alloy contains about 1.0 to less than 2.0 wt. % Be.