Effect of interfacial reaction on bending strength of Al{sub 18}B{sub 4}O{sub 33}-reinforced aluminum composites

Journal Article · Fri May 01 04:00:00 EDT 1998 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-998-0367-8· OSTI ID:616270

Yao, L J; Sasaki, G; Pan, J; Yoshida, M; Fukunaga, H ^[1]

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1. Hiroshima Univ., Higashi-Hiroshima (Japan). Dept. of Mechanical Engineering

The present study deals with the mechanism of the interfacial reaction and the microstructure of the interface in aluminum borate whisker-reinforced pure aluminum matrix composites prepared by a squeeze casting process. By means of X-ray diffraction analysis (XRDA), differential thermal analysis (DTA), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM), it has been found that no interfacial reaction occurred under the as-cast condition, whereas aluminum reacted with the whiskers when the composite was reheated at a temperature higher than 726 C. The reaction produced {gamma}-Al{sub 2}O{sub 3}. Based on HRTEM observation, it is considered that the whiskers bond to the aluminum matrix directly after squeeze casting. The observation also shows that there is a specific orientation relationship between the reaction product and whisker, {l_brace}002{r_brace} Al{sub 18}B{sub 4}O{sub 33} {parallel} {l_brace}220{r_brace} {gamma}-Al{sub 2}O{sub 3}, <200> Al{sub 18}B{sub 4}O{sub 33} {parallel} <111> {gamma}-Al{sub 2}O{sub 3}, which leads to a coherent interface with a mismatch of less than 1 pct. The interfacial bonding state changed after heating under different conditions. Propagation of cracks in each interfacial state was observed by SEM, and the effects of the interfacial reaction on the bending strength were studied with the microstructure of the interface.

• Sponsoring Organization: USDOE
• OSTI ID: 616270
• 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: 5 Vol. 29; ISSN 1073-5623; ISSN MMTAEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
ALUMINIUM COMPOUNDS
BORATES
CHEMICAL REACTIONS
COMPOSITE MATERIALS
FLEXURAL STRENGTH
INTERFACES
MICROSTRUCTURE