[T15] Hard Materials

[16F-T15-03] Tensile Strength of Ultrafine-Grained Cemented Carbide Containing Ti(C,N)

*T. Tsutsumi^1,2, M. Takada², S. Terasaka^2,3, N. Watanabe², H. Matsubara² (1.Nippon Tokushu Goukin Co.Ltd., Japan, 2.Graduate School of Environment Studies, Tohoku university, Japan, 3.Japan Fine Ceramics Center, Japan)

キーワード：cemented carbide, ultrafine-grained, tensile strength, bending strength, defect size

The strength of cemented carbides is generally measured by bending tests. However, after the bending test of ultrafine-grained cemented carbides, the specimens were broken in many fragments, so that defect is hard to be observed. This fragmentation prevented a clear understanding of the relationship between the defect and stress, as the precise locations and sizes remained unknown. While bending tests have complicated stress condition with tension, compression and shear, tensile tests are simple about stress condition. Therefore, the purpose of investigation is to clarify the relationship between the defect size and strength by conducting tensile tests on ultrafine-grained cemented carbides. The number of fragments after a tensile test on ultrafine-grained cemented carbide is much less than the number of fragments after a bending test. Therefore, it is possible to observe the defect in tensile tests. As the defect size decreased, ultrafine-grained alloy has slightly increased strength.