NbC-BASED CERMET PRODUCTION COMPARISON: L-PBF ADDITIVE MANUFACTURING VERSUS CONVENTIONAL LPS POWDER METALLURGY

Author(s)

Miranda, Fabio ; dos Santos, Marcelo Otavio ; Rodrigues, Daniel ; Coelho, Rodrigo Santiago ; Batalha, Gilmar Ferreira

• Document type: Journal article
• Source: MATERIALI IN TEHNOLOGIJE; v. 57, n. 5, p. 9-pg., 2023-01-01.

Abstract

The production of carbide parts (cermet) by additive manufacturing, such as laser powder bed fusion (L-PBF), has been a great challenge due to the complex optimization of process parameters to improve density, porosity, microcracks or abnormal growth of grains and obtain a microstructure as homogeneous as possible. This work aims to compare the evolution of the microstructure when using the conventional route of powder metallurgy, i.e., liquid phase sintering (LPS) with the L-PBF direct additive manufacturing process, considering the NbC-based carbide material. Sample compositions were prepared in w/%, sam -ples were compacted under 50-125 MPa, without polymeric binders, and they were sintered under a vacuum at temperatures of 1330 degrees C and 1370 degrees C. For the L-PBF process, a vibrating device made it possible to improve the fluidity of the mixtures of three alloys, NbC-30Co, NbC-30Ni and NbC-30(Co, Ni). The mixtures exhibited low sphericity, low fluidity and compressibility, which were improved with a roller compactor. Thin powder mixture deposition layers were evenly applied and well distributed across the powder bed to avoid defects and cracks during sintering. The L-PBF process parameters varied including a power of 50-125 W and a laser scanning speed of 25-125 mm center dot s-1. Different microstructures, identified with a light microscope (LM) and a scanning electron microscope (SEM), and properties obtained with the two processes, direct (L-PBF) and indirect sintering (LPS), were compared. (AU)

• FAPESP's process: 19/08927-2 - Circular economy and urban mining for the sustainable development of the production of hardmetals based on tungsten carbide-cobalt (WC-Co)
• Grantee: Fabio Miranda
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
• FAPESP's process: 22/06201-7 - Circular economy and urban mining for the sustainable development of the production of hardmetals based on tungsten Carbide-Cobalt (WC-Co)
• Grantee: Fabio Miranda
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE