Characteristics of structure and properties of a sintered graded tool materials with cobalt matrix

Purpose: The mechanical alloying (MA) method has been chosen to manufacture tool gradient materials with high disproportion of cobalt matrix portion between core and surface layer. Design/methodology/approach: The following research studies have been carried out to elaborate a new group of sintered tool gradient materials, tungsten carbide with cobalt matrix, to elaborate their fabrication technology and to determine their structure and properties: a fabrication technology of mixtures and the formation technology of tungsten carbide gradient materials with cobalt matrix WC-Co was applied and elaborated; sintering conditions were selected experimentally, ensuring the best structure and properties; phase and chemical composition of the sintered gradient WC-Co materials was determined using EDX; the structure of sintered gradient WC-Co materials was investigated using scanning microscopy; mechanical and physical properties of sintered gradient WC-Co materials was determined: hardness, resistance to abrasive wear, resistance to brittle cracking. Findings: The presented research results confirm that the methods of mixing tungsten carbide in cobalt matrix an important effect upon the grain size of mixture. But it is not possible to determine the changes in grain size distribution. The larger particles break down rapidly that the product becomes more uniform. Practical implications: The material presented in this paper is characterized by very high hardness of the surface and relative ductility of the core. Originality/value: The obtained results show the possibility to manufacture TGMs on the basis of different portions of cobalt reinforced with hard ceramics particles in order to improve the abrasive resistance and ductility of tool cutting materials.