On structure and mechanical properties of ultrasonically cast Al-2% Al{sub 2}O{sub 3} nanocomposite

Journal Article · Wed May 06 04:00:00 EDT 2009 · Materials Research Bulletin

DOI:https://doi.org/10.1016/j.materresbull.2008.09.040· OSTI ID:21199777

Mula, S; Padhi, P; Panigrahi, S C; Pabi, S K ^[1]

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1. Metallurgical and Materials Engineering Department, Indian Institute of Technology, Kharagpur 721302 (India)

An investigation on the structure of an ultrasonically cast nanocomposite of Al with 2 wt.% nano-sized Al{sub 2}O{sub 3} (average size {approx}10 nm) dispersoids showed that the nanocomposite was consisting of nearly continuous nano-alumina dispersed zones (NDZs) in the vicinity of the grain boundaries encapsulating Al{sub 2}O{sub 3} depleted zones (ADZs). The mechanical properties were investigated by nanoindentation and tensile tests. The nano-sized dispersoids caused a marginal increase in the elastic modulus, and a significant increase in the hardness ({approx}92%), and tensile strength ({approx}48%). Subsequent cold rolling to achieve a reduction ratio of 2 resulted in an appreciable increase in the hardness due to change in morphology of the microstructure. Estimation of the strength on the basis of inter-particle spacing, which was measured by transmission electron microscopy, could not be accounted for on the basis of Orowan mechanism, and therefore, strengthening mechanisms like local climb and/or cross slip might have a role in this room temperature (0.32T{sub M}) deformation process.

• OSTI ID: 21199777
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 5 Vol. 44; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
DEFORMATION
GRAIN BOUNDARIES
HARDNESS
MORPHOLOGY
NANOSTRUCTURES
TEMPERATURE RANGE 0273-0400 K
TENSILE PROPERTIES
TRANSMISSION ELECTRON MICROSCOPY