Effect of heat treatment on the microstructure, tensile properties, and fracture behavior of permanent mold Al-10 wt pct Si-0. 6 wt pct Mg/SiC/10[sub p] composite castings

Journal Article · Sat Oct 01 00:00:00 EDT 1994 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

OSTI ID:6996007

Samuel, F H; Samuel, A M ^[1]

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1. Univ. of Quebec, Chicoutimi (Canada). Dept. of Applied Sciences

The present study was undertaken to investigate the effect of solution treatment and artificial aging on the variation in the microstructure, tensile properties, and fracture mechanisms of Al-10 wt pct Si-0.6 wt pct Mg/SiC/10[sub p] composite castings. In the as-cast condition, the SiC particles are observed to act as nucleation sites for the eutectic Si particles. Increasing the solution temperature results in faster homogenization of the microstructure. Effect of solution temperature on tensile properties is evident only during the first 4 hours, after which hardly any difference is observed on increasing the solution temperature from 520 C to 550 C. The tensile properties vary significantly with aging time and temperature. Prolonged solution treatment at 550 C for 24 hours results in a slight improvement in the ductility of the aged test bars. The fracture surfaces exhibit a dimple morphology and cleavage of the SiC particles, the extent of SiC cracking increasing with increasing tensile strength and reaching a maximum in the over aged condition. Microvoids act as nucleation sites for the formation of secondary cracks that promote severe cracking of the SiC particles. A detailed discussion of the fracture mechanism is given.

• OSTI ID: 6996007
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Vol. 25:10; ISSN 0360-2133
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
COMPOSITE MATERIALS
SILICON ALLOYS
SILICON CARBIDES
FRACTURE PROPERTIES
MAGNESIUM ADDITIONS
TEMPERATURE DEPENDENCE
ALLOYS
ALUMINIUM ALLOYS
CARBIDES
CARBON COMPOUNDS
MAGNESIUM ALLOYS
MATERIALS
SILICON COMPOUNDS
360603* - Materials- Properties
360602 - Other Materials- Structure & Phase Studies