炭化チタン-グラファイト系複合材料の製造と特性 : 第1報,炭化チタン及び微量グラファイト添加炭化チタンの機械的特性と微細構造

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Titanium carbide and its composites incorporated with 1, 3, 5 and 10 wt% of graphite were consolidated by hot-pressing at temperatures ranging from 1800°to 2100℃. Although significant grain growth occurred in the monolithic TiC at higher hot-pressing temperatures, the graphite addition inhibited the grain growth well in the composites. Room-temperature bending strength, σ, of the monolithic TiC correlated with the average grain diameter, d, through the Hall-Petch relation (σ∝d^<-1/2>). Such a correlation may be attributed to intrinsically existing surface flaws with size dominated by average grain size. Fracture toughness of the monolithic TiC increased linearly with the average grain diameter, in accordance with an increase in effective surface energy. The graphite addition resulted in strengthening of the TiC through the inhibition of both grain growth and crack propagation ; however, excess addition of graphite (more than 3 wt%) caused strength reduction in the composites due to graphite agglomeration which acts as a fracture origin. Fracture toughness of the TiC also increased with graphite addition through deflection and bridging of the cracks by graphite particles.
一般社団法人日本機械学会の論文
1993-08-25