Effects of addition of magnesium on interface structure and high-strain-rate superplasticity in Si{sub 3}N{sub 4}-reinforced Al-alloy composites

Journal Article · Mon Nov 02 04:00:00 EST 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(98)00282-1· OSTI ID:302343

Jeong, H G; Hiraga, K ^[1]; Mabuchi, M ^[2]; Higashi, K ^[3]

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1. Tohoku Univ., Sendai (Japan). Inst. for Materials Research
2. National Industrial Research Inst. of Nagoya (Japan)
3. Osaka Prefecture Univ., Sakai, Osaka (Japan). Dept. of Metallurgy and Materials Science

The mechanical properties and interface structure of fine-grained Al-Cu alloy and Al-Cu-Mg alloy composites, reinforced with Si{sub 3}N{sub 4} whiskers (Si{sub 3}N{sub 4}w) and particles (Si{sub 3}N{sub 4}p), are investigated to reveal the role of magnesium addition in high-strain-rate superplasticity. The Al-Cu alloy composites, which exhibit lower elongations (< 100%), have clear interfaces between the Al-matrix and Si{sub 3}N{sub 4} crystals without any interfacial reaction. On the other hand, the interfaces in the Al-Cu-Mg alloy composites, which exhibit high elongations (> 280%), show strong reaction between the Al-matrix and Si{sub 3}N{sub 4} crystals. The result suggests that the addition of magnesium causes the reaction between the Al-matrix and Si{sub 3}N{sub 4} crystals, and consequently that partially melting of the reaction phases at the tensile-testing temperature results in the relaxation of stress concentration and suppresses the development of microcracks and cavities at the interfaces during superplastic deformation.

• OSTI ID: 302343
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 17 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
COMPOSITE MATERIALS
COPPER ALLOYS
DEFORMATION
INTERFACES
MAGNESIUM ALLOYS
METALLURGICAL EFFECTS
MICROSTRUCTURE
PLASTICITY
SILICON NITRIDES