Mechanical behavior and failure micromechanisms of Al/Al{sub 2}O{sub 3} composites under cyclic deformation
- Polytechnic Univ. of Madrid (Spain). Dept. of Materials Science
The mechanical behavior under fully reversed cyclic deformation was determined through the incremental step method for two Al alloys reinforced with 15 vol pct Al{sub 2}O{sub 3} particulates in the naturally aged and peak-aged conditions. The composites exhibited cyclic strain hardening in all cases, but the hardening was more pronounced in the naturally aged condition. This behavior was reflected by the stress-strain curves in monotonic tension and in fatigue, and the cyclic strain-hardening coefficient was about twice the monotonic one for both materials and tempers. The tensile and cyclic strengths of the materials were very similar, and the dominant failure mechanism under both loading conditions was particulate fracture, which was very localized around the fracture region in fatigue, but was spread along the specimen length in monotonic tension. In addition, a few Al{sub 2}O{sub 3} particulates were broken in compression during cyclic deformation. The final fracture micromechanism was the growth and coalescence of voids in the matrix from broken ceramic particulates. This last stage in the fracture process was fast and started when a critical volume fraction of broken reinforcements (between 30 and 45 pct) was reached in a given section of the specimen.
- OSTI ID:
- 205247
- Report Number(s):
- CONF-940204-; ISSN 0360-2133; TRN: IM9615%%27
- Journal Information:
- Metallurgical Transactions, A, Vol. 26, Issue 12; Conference: 123. annual meeting of the Minerals, Metals and Materials Society, San Francisco, CA (United States), 27 Feb - 3 Mar 1994; Other Information: PBD: Dec 1995
- Country of Publication:
- United States
- Language:
- English
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