Flexural Strength Reduction in Cemented Carbides

Cemented carbides are hard materials used in tough materials machining as well as in situations where other tools would wear away. These are one of the most successful composite engineering materials ever produced. The advantage of cemented carbides is that their structure and composition can be engineered to have properties tailored to specific applications and operations. These materials allow faster and more precise machining and will leave a better surface finish. Carbide tools can also withstand higher temperatures than standard high speed steel tools. Considering their application and known range of properties, main disadvantage of cemented carbides is appearance of their sudden fracture during machining process. This is caused by the low toughness at dynamic rates and overcoming this problem is yet to be researched further. In order to understand these limitations and provide suggestions for the improved design of the material, combined experimental and numerical analysis is currently being performed. Cohesive strength values numerically determined using Dugdale cohesive zone model are compared to flexural strength obtained experimentally. Reduction in flexural strength was then analysed and explained, relating it to the flaw size on the tensile surface of the specimen.