INFLUENCE OF POWDER CHARACTERISTICS ON THE SPREADABILITY OF PRE-ALLOYED TUNGSTEN- CARBIDE COBALT

• Preyin Govender Department of Mechanical and Mechatronic Engineering, DSI-NRF Centre of Excellence in Strong Materials, Stellenbosch University
• Deborah Clare Blaine Department of Mechanical and Mechatronic Engineering, DSI-NRF Centre of Excellence in Strong Materials Stellenbosch University
• Natasha Sacks Department of Industrial Engineering, DSI-NRF Centre of Excellence in Strong Materials Stellenbosch University

DOI:

https://doi.org/10.7166/32-3-2664

Keywords:

Additive Manufacturing, Spreadability, WC-Co, Laser Powder Bed Fusion, Powder Characterization

Abstract

With rising interest in additive manufacturing (AM) techniques, there is an increased focus on research that evaluates critical parameters that guide the selection of powders that are suitable for AM. One such parameter is a powder’s spreadability, described by metrics such as powder bed density and percentage coverage. This study focused on three spray-dried WC-Co powders (two 12 wt% and one 17 wt% Co) and evaluated the influence of typical powder characteristics, such as particle size and shape, apparent density, and flow rate, on their spreadability. It was found that particle size distribution influenced the powder spreadability. Larger particles hindered the even spreading of powder over the base plate, resulting in low powder bed density and percentage coverage. This also correlated with the powders’ apparent densities. The flow rate and angle of repose gave an indication of how cohesive the powders are. The more cohesive a powder, the poorer the spreadability, resulting in a lower powder bed density and percentage coverage.