Recycling of metal matrix composites
US4992241A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 1990 |
| Grant date | Feb 12, 1991 |
| Priority date | — |
| Expiry date | Mar 15, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22B21/064
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process is described for recycling scrap aluminum-matrix composites, e.g. gates and risers from a casting operation. A melt of the scrap composite is provided in a treatment vessel by heating at a temperature of 720.degree.-750.degree. C., such as to avoid unwanted stirring and contamination of the melt. While mixing with the impeller, a gas is injected through a gas outlet beneath the surface of the melt and near the rotating impeller. This melt is mixed with a vaned rotor impeller such that no vortex is formed and oxide film is not drawn into the melt. This treatment gas comprises a mixture of a major proportion of an inert gas and a minor proportion of reactive gas. The gas injection is continued only until small gas bubbles have been well distributed through the melt but before the gas causes the reinforcing parties to start rising to the surface. After the gas is stopped, the melt is allowed to rest for a period of time at the reaction temperature of 720.degree.-750.degree. C. with at least periodic gentle mixing to keep the reinforcing particles distributed evenly throughout the melt. During this treatment, hydrogen is removed from the melt by diffusion into the gas bubbles…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.