Method for producing an aluminium alloy foam by moulding

Patent metadata

Field	Value
Publication number	US-9650696-B2
Application number	US-201314405983-A
Country	US
Kind code	B2
Filing date	Jun 20, 2013
Priority date	Jun 29, 2012
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A method for producing an aluminum alloy foam wherein an aluminum alloy, in molten form, infiltrates the interstices of a preform of silicon elastomer elements, by means of a conventional molding process, typically a low-pressure process, followed by the elimination of the preform broken down into silica powder during the molding cycle and/or an additional baking cycle.

First claim

The invention claimed is:

1. A method for manufacturing an aluminium alloy foam having open cells with a porosity of from 60% to 80%, wherein the method comprises:
extruding a silicone elastomer through a die to form silicone elastomer elements;
cutting each of the extruded silicone elastomer elements into portions of silicone elastomer elements, each of said portions having a similar length;
agglomerating the portions of silicone elastomer elements;
polymerizing the agglomerated portions of silicone elastomer elements in a moulding tool to form a preform;
removing the preform from the moulding tool;
storing the preform at a temperature of from 80° C. to 150° C.;
placing the preform into a mould;
casting an aluminium alloy in the mould at a temperature of from 800° C. to 820° C., and at a pressure of from 700 mbar to 1.5 bar, to allow the alloy to penetrate into interstices of the preform, thereby forming an aluminium alloy foam and silica powder; and
removing the aluminium alloy foam from the mould.

2. The method according to claim 1 , wherein the portions are formed as substantially spherical balls before the agglomeration step.

3. The method according to claim 1 , wherein the silicone elastomer elements extruded from the die have a circumscribed outside diameter of from 2 mm to 10 mm.

4. The method according to claim 1 , wherein the portions have a length of from 2 mm to 10 mm.

5. The method of claim 1 , wherein the portions are agglomerated by mixing the portions in the presence of a binder, and forming the preform in a core box mould.

6. The method according to claim 5 , wherein the binder is a liquid silicone binder.

7. The method according to claim 6 , wherein the liquid silicone binder is used in an amount of from 1% to 3% expressed as a percentage by mass.

8. The method according to claim 5 , wherein the binder is a liquid polyurethane resin binder.

9. The method according to claim 8 , wherein the liquid polyurethane resin binder is used in an amount of from 2% to 4% expressed as a percentage by mass.

10. The method according to claim 1 , wherein the preform has a density of from 0.5 to 0.8.

11. The method according to claim 1 , further comprising introducing a tube into the preform during the agglomerating step.

12. The method according to claim 11 , wherein the tube is made from aluminium alloy or borosilicate glass.

13. The method according to claim 1 , wherein the preform is preheated to a temperature of from 150° C. to 250° C. before being placed into the mould.

14. The method according to claim 1 , wherein the preform has a minimum size of 50 mm×50 mm, and a thickness of from 10 to 100 mm, and a maximum size of 350 mm×350 mm, and a thickness of from 15 to 80 mm.

15. The method of claim 1 , wherein the polymerizing step is a natural polymerizing step or a forced polymerizing step.

16. The method of claim 15 , wherein the forced polymerizing step is carried out by stoving at a temperature of from 50° C. to 100° C.

17. The method of claim 1 , wherein the portions are agglomerated by directly clamping in a core box mould tool or in a press forming tool.

18. The method of claim 1 , comprising casting the aluminium alloy at a pressure of from 700 mbar to 1.0 bar.

19. The method of claim 1 , further comprising stoving aluminium alloy foam at a temperature of from 400° C. to 450° C., and discharging the silica powder.

20. The method of claim 1 , wherein the silica powder is discharged by a member selected from the group consisting of manual knocking out, vibrating, blowing, water under pressure, and a combination thereof.

Assignees

• Constellium Issoire

Inventors

• Maffeis Michel
• Trincat Francois

Classifications

• C22C21/02

  with silicon as the next major constituent · CPC title

• C22C21/06

  with magnesium as the next major constituent · CPC title

• B22D18/04

  Low pressure casting, i.e. making use of pressures up to a few bars to fill the mould · CPC title

• C22C1/082

  with removal of the preform · CPC title

• B22D29/003

  using heat · CPC title