✍ Scribed by G.-J. Zhang; Y. Beppu; T. Ohji
No coin nor oath required. For personal study only.
The reaction mechanism and microstructure development of strain tolerant in situ SiC-BN composites fabricated from the in situ reaction of Si 3 N 4 , B 4 C and C were investigated. This exothermic reaction took place at about 1400°C in an argon atmosphere according to the results of X-ray diffraction analysis and differential thermal analysis. The reaction finished after hot pressing at 1700°C for 60 min, and densification occurred mainly in the temperature range of 1700°C to 2000°C. In spite of poor sinterability of BN, composites with rather high density were obtained. Chemical composition analysis of the composites obtained showed that there was no obvious change in the composition after hot pressing. The in situ formed SiC was of the β-type with a quasi-spherical shape, whereas the in situ BN was graphitic hexagonal with a flake shape, and was located at the grain boundaries of SiC. The composite obtained showed a very fine and homogeneous microstructure. The bending strength of the composite was high, while the elastic modulus decreased substantially.
📜 SIMILAR VOLUMES
In this paper, 2 vol% TiC/Ti-1100 composites were fabricated using in situ technologies, and the b transus temperature of the composite was measured by metallographic techniques. The ingots after breakdown were forged in various temperature ranges, i.e. in the b phase field, in the (a + b) phase fie