US5009844A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for manufacturing spheroidal hypoeutectic aluminum alloy
Assignee: GM Global Technology Operations LLC
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Filing: 1989-12-01
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Granted: 1991-04-23
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Expires: 2009-12-01
Abstract
Abstract A semi-solid metal-forming process for producing an article of a hypoeutectic aluminum-silicon alloy comprises heating a solid billet of the alloy to a temperature intermediate the liquidus temperature and the solidus temperature at a rate not greater than 30° C. per minute, preferably not greater than 20° C. per minute, to form a semi-solid body of the alloy while inhibiting the formation of free silicon particles therein. The semi-solid body comprises a primary spheroidal phase dispersed in a eutectic-derived liquid phase and is conducive to forming at low pressure. In one apsect of this invention, a billet having a quiescently cast microstructure characterized by primary dendrite particles in a eutectic matrix is heated at the slow rate and maintained at the intermediate temperature for a time sufficient to transform the dendrite phase into the desired spheroidal phase.
Inventors
- 👤 Venkatasubramanian Laxmanan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:41
CPC Classifications
C; C22; C22C; C22C1/00; C22C1/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
94 words
A semi-solid metal-forming process for producing an article of a hypoeutectic aluminum-silicon alloy comprising between about 5 and 12 weight percent silicon, said process comprising heating a body of hypoeutectic aluminum-silicon alloy to a temperature between the liquidus temperature and the solidus temperature to initiate partial melting of the alloy and thereby to form a semi-solid body composed of a spheroidal phase dispersed in a liquid phase, said heating being carried out at a rate not greater than 30° C. per minute and effective to inhibit formation of free silicon particles within said alloy.
Claim 2
Dependent Claim
94 words
A semi-solid metal-forming process for producing an article of a hypoeutectic aluminum-silicon alloy comprising between about 5 and 12 weight percent silicon, said process comprising heating a body of hypoeutectic aluminum-silicon alloy to a temperature between the liquidus temperature and the solidus temperature to initiate partial melting of the alloy and thereby to form a semi-solid body composed of a spheroidal phase dispersed in a liquid phase, said heating being carried out at a rate not greater than 30° C. per minute and effective to inhibit formation of free silicon particles within said alloy.
Claim 3
Dependent Claim
105 words
A process for forming an article of hypoeutectic aluminum-silicon alloy comprising between about 5 and 12 weight percent silicon, said process comprising heating a quiescently cast billet characterized by a microstructure comprising a dendritic phase dispersed in a eutectic matrix at a rate not to exceed 20° C. per minute and effective to inhibit formation of free silicon particles within the alloy, said heating being carried out to a temperature between the liquidus temperature and the solidus temperature to initiate partial melting of said alloy, and maintaining the billet at said temperature for a time sufficient to transform said dendritic phase into a spheroidal phase.
Claim 4
Dependent Claim
105 words
A process for forming an article of hypoeutectic aluminum-silicon alloy comprising between about 5 and 12 weight percent silicon, said process comprising heating a quiescently cast billet characterized by a microstructure comprising a dendritic phase dispersed in a eutectic matrix at a rate not to exceed 20° C. per minute and effective to inhibit formation of free silicon particles within the alloy, said heating being carried out to a temperature between the liquidus temperature and the solidus temperature to initiate partial melting of said alloy, and maintaining the billet at said temperature for a time sufficient to transform said dendritic phase into a spheroidal phase.
Claim 5
Dependent Claim
105 words
A process for forming an article of hypoeutectic aluminum-silicon alloy comprising between about 6 and 8 weight percent silicon, said process comprising heating a quiescently cast billet characterized by a microstructure comprising a dendritic phase dispersed in a eutectic matrix at a rate not to exceed 20° C. per minute and effective to inhibit formation of free silicon particles within the alloy, said heating being carried out to a temperature between the liquidus temperature and the solidus temperature to initiate partial melting of said alloy, and maintaining the billet at said temperature for a time sufficient to transform said dendritic phase into a spheroidal phase.
Claim 6
Dependent Claim
105 words
A process for forming an article of hypoeutectic aluminum-silicon alloy comprising between about 6 and 8 weight percent silicon, said process comprising heating a quiescently cast billet characterized by a microstructure comprising a dendritic phase dispersed in a eutectic matrix at a rate not to exceed 20° C. per minute and effective to inhibit formation of free silicon particles within the alloy, said heating being carried out to a temperature between the liquidus temperature and the solidus temperature to initiate partial melting of said alloy, and maintaining the billet at said temperature for a time sufficient to transform said dendritic phase into a spheroidal phase.
Claim 7
Dependent Claim
27 words
The process of claim 3 comprising the further steps of forming the semi-solid body into a desired configuration and quenching the formed body to produce the article.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-22 | 1994-10-22 | 1995-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-22 | 1998-10-22 | 1999-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-22 | 2002-10-22 | 2003-04-23 | $7700.00 | Window Closed / Lapsed |