Additive manufacturing techniques for WC−Co cemented carbides: Principle, progress, and perspective

Abstract

Additive manufacturing (AM) technology has emerged as a viable solution for manufacturing complex-shaped WC−Co cemented carbide products, thereby expanding their applications in industries such as resource mining, equipment manufacturing, and electronic information. This review provides a comprehensive summary of the progress of AM technology in WC−Co cemented carbides. The fundamental principles and classification of AM techniques are introduced, followed by a categorization and evaluation of the AM techniques for WC−Co cemented carbides. These techniques are classified as either direct AM technology (DAM) or indirect AM technology (IDAM), depending on their inclusion of post-processes like de-binding and sintering. Through an analysis of microstructure features, the most suitable AM route for WC−Co cemented carbide products with controllable microstructure is identified as the indirect AM technology, such as binder jet printing (BJP), which integrates AM with conventional powder metallurgy.

1. Introduction

Cemented carbides, also named as hard alloy, are composite materials primarily composed of refractory metal carbides (reinforcement phase) and binder metals (binder phase) [1]. Among these, WC−Co cemented carbide, first invented by SCHRÖTER in 1923, consists of WC as the hard phase and cobalt as the binding phase, playing a transformative and crucial role in the industrial development of modern times [2,3]. This material has found widespread applications in various fields such as metal cutting, petroleum drilling, and geological exploration and is used for manufacturing cutting tools [4], drill bits [5] and wear-resistant components [6] due to its favorable properties, such as high hardness, wear resistance and elastic modulus.

Currently, the manufacturing of WC−Co cemented carbides components is mainly achieved via injection molding, extrusion molding, and powder metallurgy (PM) [7]. Powder metallurgy and extrusion molding technologies have matured and stabilized, enabling the fabrication of cemented carbides with high hardness and without the η phase [8,9]. However, these methods are limited to simple shapes and cannot handle complex geometries. The molds for PM must be tailored to the product’s shape, extending development cycles, especially for intricate designs. Creating complex molds for cemented carbide components is often challenging or impossible. The emergence of the additive manufacturing (AM) technology provides a solution for the manufacturing of complex-shaped WC−Co cemented carbide products. AM is a novel manufacturing technique that uses CAD models to fabricate complex parts layer-by-layer. It offers rapid prototyping and mold-free shaping, overcoming traditional cemented carbide preparation limitations [10]. More and more researchers have conducted studies on WC−Co cemented carbides additive manufacturing using various AM technologies, achieving significant research progress [11−18]. Up to now, several AM processes are being applied in the manufacturing of WC−Co cemented carbide components, including selective laser melting (SLM)/selective laser sintering (SLS) [18−31], binder jet printing (BJP) [11−13,32−36], fused deposition modeling (FDM) [16,37,38], and 3D gel-printing (3DGP) [39], etc. For instance, to improve surface quality, researchers have made ef...