Young's modulus of Al/SiC P/MgAl2O4 composites with different particle size distribution of reinforcements
The effect of particle size distribution of SiC particulate reinforcements coated with colloidal SiO2 on Young´s modulus of Al/SiCp/MgAl2O4 composites fabricated by reactive infiltration was investigated. Composites were prepared from porous preforms of silica-coated α- SiC powders of 10, 54, 86, and 146 μm, 0.6 volume fraction of reinforcements and particle size distribution from monomodal to cuatrimodal. Infiltration tests with the alloy Al-13.3Mg-1.8Si (wt. %) were carried out in Ar→N2 atmosphere at 1100ºC for 60 min. The composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition to density and residual porosity measurements, Young´s modulus was evaluated by ultrasonic techniques. Results show that with increase in particles size distribution, residual porosity decreases and density and Young´s modulus of the composites are improved, the latter from 185.39 ±3.6 to 201.93 ±2.3 GPa. This is attributed to the increased metal-ceramic interfaces and to an enhanced matrix-reinforcement load transmission.
| Main Authors: | , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Laboratório de Hidrogênio, Coppe - Universidade Federal do Rio de Janeiro
2010
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1517-70762010000200021 |
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