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Tungsten carbide (WC) is well known as one of the hardest materials widely used in machining, cutting and drilling, especially for cutting tools production. Knowing fracture toughness grants the opportunity to prevent catastrophic wear of a tool. Moreover, fracture toughness of WC-based materials may vary because of different material compositions, as well as a different way of production. Hence, each material should be treated individually. In this paper, SM25T (HW) tungsten carbide (HW—uncoated grade, TNMR 401060 SM25T, manufactured by Baildonit company, Katowice, Poland) was taken into consideration. Sintered carbides—designated as S—are designed to be applied for machining steel, cast steel and malleable cast iron. Fracture mechanics methods were adapted to make a quality assessment of WC cutting inserts. Both quasi-statical three-point bending tests, as well as Charpy dynamic impact tests, were performed to calculate static and dynamic fracture toughness (KIC and KID, respectively). In addition, a special emphasis was placed on the microscopic analysis of fracture surfaces after impact tests to discuss material irregularities, such as porosity, cracks and so-called “river patterns”. There is a lack of scientific works in this field of study. However, cutting engineers are interested in obtaining the experimental results of that kind. Although there are a few standardized methods that may be used to determine fracture toughness of hard metals, none of them is expected to be the most reliable. Moreover, there is a lack of scientific works in the field of determining static and dynamic fracture toughness of WC by the presented method. The proposed examination solution can be then successfully used to calculate toughness properties of WC-based materials, as the results obtained seem to be with a good agreement with other works.

The paper investigates experimental results of static and dynamic fracture toughness. The three-point bending test and the Charpy pendulum test were performed for two kinds of polymers: Epidian 5 epoxy resin cured with Z1 curing agent and Epidian 53 epoxy resin cured with Z1 curing agent. The comparison between the values of a maximum static and a maximum dynamic force are discussed as well as the values of static and dynamic fracture toughness, with special emphasis on microscopic views of crack propagation.

The paper investigates the growing popularity of composite materials concentrating on explanation of their advantages, especially taking into consideration composite materials used in the aerospace industry such as polymer matrix composites, metal matrix composites, ceramic matrix composites and smart composite materials. Various types of matrices and fibers are described with special emphasis on nanotechnology and opportunities to improve the properties of composites. The paper also presents selected examples of applications in the aerospace industry.

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