Superplastic behavior and cavitation in high-strain-rate superplastic Si{sub 3}N{sub 4p}/Al-Mg-Si composites

Journal Article · Sun Feb 01 04:00:00 EST 1998 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-998-0148-4· OSTI ID:611593

Iwasaki, Hajime; Mori, Takasuke ^[1]; Mabuchi, Mamoru ^[2]; Higashi, Kenji ^[3]

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1. Himeji Inst. of Tech., Hyogo (Japan). Dept. of Materials Science and Engineering
2. National Industrial Research Inst. of Nagoya (Japan)
3. Osaka Prefecture Univ., Osaka (Japan). Dept. of Metallurgy and Materials Science

High-strain-rate superplastic behavior has been investigated for Si{sub 3}N{sub 4p}/Al-Mg-Si (6061) composites with a V{sub f} = 20 and 30 pct, respectively, where V{sub f} is the volume fraction of reinforcements. A maximum elongation was attained at a temperature close to the onset temperature for melting for both composites. The maximum elongation for the 30 vol pct composite was larger than that for the 20 vol pct composite. Development of cavities transverse to the tensile direction is responsible for the lower maximum elongation of the 20 vol pct composite. However, development of the transverse cavities was limited to the optimum superplastic temperature for the 30 vol pct composite. The differential scanning calorimetry (DSC) investigation showed that a sharp endothermic peak appeared for the 30 vol pct composite, indicating that sufficient partial melting occurs. It is, therefore, likely that the stress concentrations are sufficiently relaxed by a liquid phase and that the development of transverse cavities is limited for the 30 vol pct composite.

• Sponsoring Organization: Ministry of Education, Science and Culture (Japan); Department of the Army, Washington, DC (United States)
• OSTI ID: 611593
• 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: 2 Vol. 29; ISSN MMTAEB; ISSN 1073-5623
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
CAVITIES
COMPOSITE MATERIALS
ELONGATION
MAGNESIUM ALLOYS
MELTING POINTS
PARTICULATES
PHASE TRANSFORMATIONS
PLASTICITY
SILICON ALLOYS
SILICON NITRIDES