Enhancing the Mechanical Properties of Co-Cr Dental Alloys Fabricated by Laser Powder Bed Fusion: Evaluation of Quenching and Annealing as Heat Treatment Methods

• Published in: Materials 2024-10, Vol.17 (21), p.5313
• Main Authors: Konieczny, Bartlomiej, Szczesio-Wlodarczyk, Agata, Andrearczyk, Artur, Januszewicz, Bartlomiej, Lipa, Sebastian, Zieliński, Rafał, Sokolowski, Jerzy
• Format: Article
• Language: English
• Subjects: 3-D printers; Alloys; Annealing; Beds (process engineering); Cobalt base alloys; Cooling rate; Crack initiation; Degassing of metals; Dental alloys; Dentistry; Diamond pyramid hardness; Face centered cubic lattice; Fracture mechanics; Heat treatment; Heating; Homogeneity; Homogenization; Innovations; Lasers; Manufacturing; Materials fatigue; Mechanical properties; Metals; Methods; Microcracks; Microstructure; Powder beds; Powders; Production methods; Residual stress; Silicones; Specialty metals industry; Temperature; Tensile strength; Thermal properties; Velocity; Water quenching
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17215313

Residual stresses and anisotropic structures characterize laser powder bed fusion (L-PBF) products due to rapid thermal changes during fabrication, potentially leading to microcracking and lower strength. Post-heat treatments are crucial for enhancing mechanical properties. Numerous dental technology laboratories worldwide are adopting the new technologies but must invest considerable time and resources to refine them for specific requirements. Our research can assist researchers in identifying thermal processes that enhance the mechanical properties of dental Co-Cr alloys. In this study, high cooling rates (quenching) and annealing after quenching were evaluated for L-PBF Co-Cr dental alloys. Cast samples (standard manufacturing method) were tested as a second reference material. Tensile strength, Vickers hardness, microstructure characterization, and phase identification were performed. Significant differences were found among the L-PBF groups and the cast samples. The lowest tensile strength (707 MPa) and hardness (345 HV) were observed for cast Starbond COS. The highest mechanical properties (1389 MPa, 535 HV) were observed for the samples subjected to the water quenching and reheating methods. XRD analysis revealed that the face-centered cubic (FCC) and hexagonal close-packed (HCP) phases are influenced by the composition and heat treatment. Annealing after quenching improved the microstructure homogeneity and increased the HCP content. L-PBF techniques yielded superior mechanical properties compared to traditional casting methods, offering efficiency and precision. Future research should focus on fatigue properties.