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Creep Rate Decrease in Superplastic Al Zn Alloys

IP.com Disclosure Number: IPCOM000093554D
Original Publication Date: 1967-Nov-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Chaudhari, P: AUTHOR

Abstract

The Al-Zn alloy of eutectoid composition Al + 78 wt. % Zn exhibits superplasticity when cooled rapidly from above the invariant temperature of 275 degrees C. A product manufactured using the superplastic properties of this alloy has a relatively high creep rate at room and elevated temperatures. This heat treatment lowers the high creep rate by factors of 10/5/ to 10/5/ without affecting the superplastic properties.

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Creep Rate Decrease in Superplastic Al Zn Alloys

The Al-Zn alloy of eutectoid composition Al + 78 wt. % Zn exhibits superplasticity when cooled rapidly from above the invariant temperature of 275 degrees C. A product manufactured using the superplastic properties of this alloy has a relatively high creep rate at room and elevated temperatures. This heat treatment lowers the high creep rate by factors of 10/5/ to 10/5/ without affecting the superplastic properties.

After the product is manufactured utilizing the superplastic properties, it is heated to above the invariant temperature of 275 degrees C, where it is held until the two phases alpha + beta transform to the gamma-phase. On completion of this transformation, the product is placed in a furnace maintained at a temperature between 160 degrees C and the invariant temperature until the gamma-phase transforms to the two phases alpha + beta.

By increasing the holding temperature to values larger than 160 degrees C but below the invariant temperature as described, the creep rate is decreased when the alloy is returned to ambient temperature from that creep rate it has prior to this treatment.

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