Creep strengthening in a discontinuous SiC-Al composite
- Univ. of California, Irvine, CA (United States)
High-temperature strengthening mechanisms in discontinuous metal matrix composites were examined by performing a close comparison between the creep behavior of 30 vol pct SiC-6061 Al and that of its matrix alloy, 6061 Al. Both materials were prepared by powder metallurgy techniques. The experimental data show that the creep behavior of the composite is similar to that of the alloy in regard to the high apparent stress exponent and its variation with the applied stress and the strong temperature dependence of creep rate. By contrast, the data reveal that there are two main differences in creep behavior between the composite and the alloy: the creep rates of the composite are more than one order of magnitude slower than those of the alloy, and the activation energy for creep in the composite is higher than that in the alloy. Analysis of the experimental data indicates that these similarities and differences in creep behavior can be explained in terms of two independent strengthening processes that are related to (a) the existence of a temperature-dependent threshold stress for creep, {tau}{sub 0}, in both materials and (b) the occurrence of temperature dependent load transfer from the creeping matrix (6061 Al) to the reinforcement (SiC).
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 205246
- Report Number(s):
- CONF-940204--
- Journal Information:
- Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 12 Vol. 26; ISSN 0360-2133; ISSN MTTABN
- Country of Publication:
- United States
- Language:
- English
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