Binder jetting 3D printed cemented carbide: Mechanical and wear properties of medium and coarse grades

Abstract

Selective laser melting (SLM) is the most widely used additive manufacturing (AM) technology to 3D print metals. Several researchers have tried, unsuccessfully, to produce cemented carbide by SLM. Binder jetting 3D printing (BJT) and micro-extrusion-based methods are 2 AM technologies that have been successfully applied to the printing and sintering of cemented carbide. We report the development of medium and coarse WC-Co powders for BJT with Co contents of 10%, 12%, and 17%. The free flowable (Carney flow <20 s/200 g) spherical powders exhibit very good printability and can be sintered to full density under standard sinter-HIP conditions (temperature 1435-1485 °C, pressure 18–50 bar). The sintered mechanical properties, hardness, and fracture toughness, compare well against cemented carbides produced by powder metallurgy. Vickers hardness and fracture toughness (determined by the Palmquist method) are in the range HV30 990–1300 and 17–23 MN·m-3/2, respectively. We evaluated the wear properties under abrasion and erosion using the ASTM B611 and ASTM G65 standard testing procedures. The wear resistance of the BJT cemented carbide matches, and, in some cases, can exceed the resistance of conventionally produced cemented carbide. We have manufactured components of varying geometric complexity with weights ranging from 0.53 g to 21 kg. BJT enables the manufacture of components that are not feasible by pressing and sintering, even with extensive use of green machining.