Crack healing and stress relaxation in Al2O3-SiC nanocomposites
Crack healing and stress relaxation in Al2O3-SiC nanocomposites
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DOI：
10.1111/j.1151-2916.1995.tb08215.x
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发表时间：
1995-03
影响因子：
3.9
通讯作者：
A. M. Thompson;H. M. Chan;M. Harmer;Robert E. Cook
中科院分区：
文献类型：
--
作者：
A. M. Thompson;H. M. Chan;M. Harmer;Robert E. Cook
The crack-healing behavior of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-SiC nanocomposite was studied using Vickers indentations to generate precracks. After annealing in argon for 2 h at 1,300 C, radial cracks in the nanocomposite healed: The cracks closed and there was a small degree of rebonding in the vicinity of the crack tip. In contrast, radial cracks in alumina grew when exposed to the same annealing treatment. The different responses are attributed to the fracture mode and toughening mechanism in each material: In the nanocomposite, the cracks close as the residual stresses surrounding the indentations relax. Radial cracks open and grow in Al{sub 2}O{sub 3} because microstructural toughening is diminished during heating to the annealing temperature. An implication is that strength-limiting machining flaws in these materials behave similarly, thereby accounting for the strengthening effect of annealing in this ``nanocomposite`` system.
