Internal stress and solid solubility effects on the thermal expansivity of Al-Si eutectic alloys
Thermal expansion measurements are reported for a number of as-cast Al-Si eutectic alloys including a Sr-modified alloy which gives nearly spherical Si particles. The measurements were obtained by heating and cooling over repeated temperature cycles between room temperature and 500/degree/C. In general, lower expansivity values were measured on the cooling cycle as compared with the heating cycle, resulting in a net positive permanent deformation at room temperature. Analytical solutions are described for the thermal expansivity of a concentric-spheres model for a Si particle contained within an Al matrix. The effect of plastic flow in the Al is included. Overall, the predictions show reasonable agreement with the measured expansivities. The observed differences between heating and cooling are of the same order as that which is predicted. At high temperatures, the measured increase in expansivities is smaller than calculated. The latter effect is explained by the decrease in expansivity which results from an increasing solid solubility of silicon in aluminum with increasing temperature.
- Research Organization:
- Naval Research Lab., Washington, DC (USA)
- OSTI ID:
- 5677893
- Report Number(s):
- CONF-861258-
- Journal Information:
- Int. J. Thermophys.; (United States), Vol. 9:2; Conference: 9. international thermal expansion symposium, Pittsburgh, PA, USA, 8-10 Dec 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM ALLOYS
THERMAL EXPANSION
SILICON ALLOYS
ANALYTICAL SOLUTION
DEFORMATION
EUTECTICS
MATHEMATICAL MODELS
PLASTICITY
SHEAR PROPERTIES
SOLID SOLUTIONS
SOLUBILITY
STRESS ANALYSIS
STRONTIUM ALLOYS
TEMPERATURE DEPENDENCE
THERMAL CYCLING
THERMAL FATIGUE
THERMAL STRESSES
ALLOYS
DISPERSIONS
EXPANSION
FATIGUE
MECHANICAL PROPERTIES
MIXTURES
SOLUTIONS
STRESSES
360103* - Metals & Alloys- Mechanical Properties
360102 - Metals & Alloys- Structure & Phase Studies
360104 - Metals & Alloys- Physical Properties