Investigation of the microstructural and mechanical properties of Al/TiB2 composites produced by cold spray additive manufacturing

Abstract

In recent years, advanced technology materials are of great interest. One of these materials, Titanium diboride (TiB2), has a very important place with its features such as high hardness, high melting point, excellent wear and corrosion resistance. TiB2 production methods; carbothermic reduction, metallothermic reduction, powder metallurgy method, aerosal process and molten salt electrolysis. TiB2 Wear plates produced by these methods can be used as cutting tools, nozzles, gaskets, high temperature fittings. It is preferred in many industrial areas due to its high hardness. However, since it complicates its machinability in shaping, it pushes TiB2 to be used as a composite rather than being used alone. Aluminum shows soft, ductile and functional properties. For this reason, the use of aluminum and TiB2 as composite gives rise to many new areas of use in the industry. One of the newest methods of using these two materials as composites is the cold spray additive manufacturing method. In this method; Unlike other additive manufacturing methods, production can be made without the use of beam welding or resin, with the help of compressed air, without melting. In this study; Pure aluminum powder and pure TiB2 powder were first produced in different components by the cold spray additive manufacturing method. After applying the microstructure and mechanical tests to these produced samples, it was decided to proceed with the sample with 30% by weight TiB2 composition. This sample was heat treated at different temperatures to reduce the stresses that occur during cold spray additive manufacturing. Next; microstructure and mechanical properties were investigated. As a result of the study; It was observed that the hardness of the Al/TiB2 composite decreased with the increase of the heat treatment temperature, that is, it became more ductile and the wear resistance increased. However, with the increase of the heat treatment temperature from 300◦C, cracks and separations in the matrix phase, gaps occurred due to the different thermal expansion coefficients of the aluminum matrix and TiB2 reinforcement material.