Article ID Journal Published Year Pages File Type
1582972 Materials Science and Engineering: A 2008 9 Pages PDF
Abstract
Rapid solidification of Al2O3/Y3Al5O12 (YAG) binary eutectic ceramic in situ composites during the remelting process using high-energy laser, which results in refinement of the solidification microstructure and improvement of the mechanical properties, is studied in this paper. The rapidly solidified Al2O3/YAG eutectic consists of Al2O3 and YAG phases without any other phases, effectively avoiding grain boundaries. The eutectic interspacing is extremely refined due to the high-temperature gradient and solidification rate of laser rapid solidification, and the minimal interspacing is as fine as 0.5 μm. The eutectic exhibits an obvious faceted-faceted eutectic growth characteristic which mainly derives from the high-fusion entropies of eutectic phases and large kinetic undercooling. The mean hardness and fracture toughness measured by an indentation technique are 17.5 GPa and 3.6 MPa m1/2, respectively. The increase of fracture toughness can be attributed to the refinement of eutectic phases which restrain and arrest crack propagations.
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Physical Sciences and Engineering Materials Science Materials Science (General)
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