The Role of Binding Phase in Hard Alloys (Analytical Review)

Abstract

A review of articles on the influence of the composition and structure of the binding phase on the properties of hard alloys is given. The role of the binding phase influencing the properties of hard alloys on the basis of data of domestic and foreign researchers is emphasized. The existing and new data on testing of the elements of periodic system as a binding phase which impacts the microstructure and properties of a hard alloy are presented. The existing and new proposals on replacing of the main element (cobalt) with iron, nickel, rhenium, molybdenum, chromium, etc., are considered in order to obtain higher properties and lower the price of the alloy. It is shown that obtaining the best operational properties in each particular case of application of the alloy requires an optimal combination of grain size and cobalt content. Various hard-alloy products are indicated for different areas of application. Techniques of reinforcement of the binding of hard alloys by means of introduction of various types of reinforcers are considered. Their influence on average grain size and properties of hard alloy is shown by examples of various grain growth inhibitors. The ways of further development of submicron, ultrathin, and nanophase alloys with a nanostructured binder reinforced with nanoparticles are presented. The way of further development of hard alloys is shown by example of alloy WC–50% Со with additions. The properties of replacing the cobalt binder with nickel alloyed with small additives are indicated: Мо, W, TiC, HfC, VC, NbC, TaC, Cr3C2.