An investigation of the role of a liquid phase in Al-Cu-Mg metal matrix composites exhibiting high strain rate superplasticity

Journal Article · Sun May 01 04:00:00 EDT 1994 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(94)90384-0· OSTI ID:5149461

Mabuchi, M ^[1]; Higashi, K ^[2]; Langdon, T G ^[3]

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1. National Industrial Research Inst., Nagoya (Japan)
2. Univ. of Osaka Prefecture, Osaka (Japan). Dept. of Mechanical Systems Engineering
3. Univ. of Southern California, Los Angeles, CA (United States). Dept. of Materials Science and Mechanical Engineering

Tensile experiments were performed under conditions of true constant strain on three Al-Cu-Mg metal matrix composites containing 20 vol.% of either [beta]-Si[sub 3]N[sub 4] whiskers or [alpha]-Si[sub 3]N[sub 4] particulates with diameters of 0.2 or 1.0 [mu]m, respectively. The tests were conducted at temperatures from 758 to 833 K and at strain rates up to 10[sup 2] s[sup [minus]1]. The results show that each composite exhibits a strain rate sensitivity of > 0.3 at strain rates in the vicinity of [approximately]10[sup [minus]1][minus]1s[sup [minus]1] and with associated superplastic elongations of > 200% or even up to > 800% for the composite with particulates having a diameter of 1.0 [mu]m. It is concluded that high ductilities are achieved at effective testing temperatures above the solidus temperature of the matrix alloy but the results are not consistent with a rheological model based on deformation in a semi-solid matrix. It is suggested instead that the presence of a liquid phase at the interfaces between the reinforcement and the matrix serves to relieve the stress concentrations due to sliding and thereby to limit the development of internal cavitation.

• OSTI ID: 5149461
• Journal Information: Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 42:5; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM BASE ALLOYS
COMPOSITE MATERIALS
COPPER ALLOYS
DATA
DEFORMATION
DUCTILITY
ELONGATION
EXPERIMENTAL DATA
INFORMATION
MAGNESIUM ALLOYS
MATERIALS
MECHANICAL PROPERTIES
NITRIDES
NITROGEN COMPOUNDS
NUMERICAL DATA
PLASTICITY
PNICTIDES
SILICON COMPOUNDS
SILICON NITRIDES
TENSILE PROPERTIES