Strength and Creep in Boron Carbide (B4C) and Aluminum Dodecaboride (α-AlB12)
✍ Scribed by T.G. Abzianidze; A.M. Eristavi; S.O. Shalamberidze
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 112 KB
- Volume
- 154
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
Some thermomechanical properties of boron carbide and aluminum dodecaboride are presented. The dependence of the bending strength on the temperature of B 4 C and AlB 12 in the ductile rupture region was studied. It was detected that the ductile rupture of B 4 C starts at temperatures above 15003C while that of AlB 12 begins at 14003C. Total deformation, however, did not exceed 2% even at 18003C. The investigation of the creep of B 4 C and AlB 12 showed that the rate d /dt of steady creep depends on the applied stress and the temperature: d /dt ؍ A n exp(؊E/RT ). Besides, creep in boron carbide at stress values lower than 90 MPa occurred by the vacancy-di4usive mechanism, for which n ؍ 1. At stress values over 90 MPa, n ؍ 3 and the creep mechanism changes to dislocation creep. A similar phenomenon is observed in the case of aluminum dodecaboride; however, the replacement of the vacancy-di4usive mechanism by dislocation creep takes place at stress values of 80 MPa.