Creep behavior of an AZ91 magnesium alloy reinforced with alumina fibers

Journal Article · Sun Aug 01 04:00:00 EDT 1999 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-999-0016-x· OSTI ID:691378

Li, Y; Langdon, T G ^[1]

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1. Univ. of Southern California, Los Angeles, CA (United States)

Creep tests were conducted at elevated temperatures on an AZ91 alloy reinforced with 20 vol pct Al{sub 2}O{sub 3} fibers. When the creep data are interpreted by incorporating a threshold stress into the analysis, it is shown that the true stress exponent, n, is {approximately}3 at the lower stress levels and increases to >3 at the higher stresses. The true activation energy for creep is close to the value anticipated for interdiffusion of aluminum in magnesium. This behavior is interpreted in terms of a viscous glide process with n = 3 and a breakaway of the dislocations from their solute atom atmospheres at the higher stress levels. The threshold stresses in this composite appear to arise from an attractive interaction between mobile dislocations in the matrix alloy and Mg{sub 17}Al{sub 12} precipitates. The experimental results reveal several important similarities between the creep behavior of this magnesium-based composite and the well-documented creep properties of aluminum-based composites.

• Sponsoring Organization: USDOE
• OSTI ID: 691378
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 8 Vol. 30; ISSN MMTAEB; ISSN 1073-5623
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
COMPOSITE MATERIALS
CREEP
DISLOCATIONS
FIBERS
MAGNESIUM BASE ALLOYS
PRECIPITATION
STRESS ANALYSIS
TEMPERATURE DEPENDENCE