On the fracture statistics of polycrystalline α-SiC at room and high temperature

✍ Scribed by A. Charif; F. Osterstock

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 261 KB
• Volume: 11
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/0921-5107(92)90228-2

✦ Synopsis

Rupture stresses have been measured at room temperature and 1473 K. It is verified how large inclusions, such as large crystals resulting from uncontrolled grain growth, may affect the rupture stress values and their true distribution as described by the Weibull modulus. Owing to their size, these large anisotropic crystals may give rise to a residual stress field. The tensile components superpose on the applied stress. Thus at room temperature the rupture stresses are underestimated, giving also an underestimate of the Weibull modulus. Computer-aided design of the reliability of structural parts should thus take this point into account, especially if generation of predefined microstructures is undertaken. The magnitude of the residual tensile stress is evaluated in two ways: as the difference between the measured and a residual-stress-free distribution and by making a calculation based on the model of a spherical inclusion. In view of the uncertainties of some data, the agreement is rather good. Extensions to whisker-reinforced polycrystalline ceramics may thus be considered.