SOME TRENDS IN IMPROVING WC–Co HARDMETALS
ІІ. FUNCTIONALLY GRADED HARDMETALS

 

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Omeliana Pritsaka str.,3, Kyiv, 03142, Ukraine
Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2019, #03/04
http://www.materials.kiev.ua/article/2815

Abstract

Research efforts on the development of hardmetals with a gradient structure, i.e., a structure that changes smoothly over the section or volume of a sample, have been analyzed. These materials are called functionally graded hardmetals and are characterized by increased wear resistance at set hardness. Three approaches to the creation of functionally graded hardmetals, which are implemented in Ukraine, Europe, and the USA, are noted. These approaches are based on one phenomenon, such as the migration of liquid cobalt from one to another hardmetal zone that differ in the size of tungsten carbide particles, liquid phase amount, and carbon content. The approaches differ by process features in preparing and sintering the samples that acquire a gradient structure. In addition, different methods to produce hardmetals with a gradient structure are described. New capabilities of the extrusion technology for the production of parts with uneven cross-sectional structure are studied. Conditions of obtaining lengthy products from hardmetals with a cellular or “honeycomb” structure by extrusion of structural elements through a die with an opening of specific shape are presented.


FRACTURE TOUGHNESS, FUNCTIONALLY GRADED MATERIAL, HARD ALLOY, HARDNESS, WEAR RESISTANCE