IADR Abstract Archives
Enhanced Fatigue Strength of SLMed Co-Cr-Mo clasp by Post-heat Treatment Clasp
Objectives: The objective of this study was to investigate the effect of post-heat treatment on the microstructures and fatigue strengths of Co-Cr-Mo (CCM) clasps prepared by SLM.
Methods: The clasp specimens and rod-shaped specimens were fabricated by SLM method using CCM powders in different angulations (0°, 45°, 90°) to apply heat treatment. Two heat treatment timeing conditions were 1 and 6 hours at 1150 °C in argon atmosphere followed by cooling in the furnace. The fatigue strength was tested with cyclic deformations of 0.50 mm, for 5Hz, at the tip. The microstructure and phase formation were analyzed by Confocal Laser Scanning Microscopy (CLSM), Scanning Electron Microscope (SEM), Field-Emission Transitional Electron Microscope (FE-TEM), and X-ray diffraction (XRD).
Results: The fatigue strengths of 0° and 45° axes were significantly improved after post heat treatment both 1 and 6 hours at 1150°C (P<0.01) compared to the control specimens. Furthermore the specimens which were heated for 1 hour exhibited higher fatigue life than 6 hours condition in all axes. In the microstructure, the control group showed inhomogeneous grain shape and fiber texture when changing building angulation. Whereas after heat treatment both 1 and 6 hours showed homogeneous equixed grain and randomized texture in all angulation.
Conclusions: The heat treatment improved the fatigue strength and reduced the anisotropy effect due to homogenized microstructure.
Methods: The clasp specimens and rod-shaped specimens were fabricated by SLM method using CCM powders in different angulations (0°, 45°, 90°) to apply heat treatment. Two heat treatment timeing conditions were 1 and 6 hours at 1150 °C in argon atmosphere followed by cooling in the furnace. The fatigue strength was tested with cyclic deformations of 0.50 mm, for 5Hz, at the tip. The microstructure and phase formation were analyzed by Confocal Laser Scanning Microscopy (CLSM), Scanning Electron Microscope (SEM), Field-Emission Transitional Electron Microscope (FE-TEM), and X-ray diffraction (XRD).
Results: The fatigue strengths of 0° and 45° axes were significantly improved after post heat treatment both 1 and 6 hours at 1150°C (P<0.01) compared to the control specimens. Furthermore the specimens which were heated for 1 hour exhibited higher fatigue life than 6 hours condition in all axes. In the microstructure, the control group showed inhomogeneous grain shape and fiber texture when changing building angulation. Whereas after heat treatment both 1 and 6 hours showed homogeneous equixed grain and randomized texture in all angulation.
Conclusions: The heat treatment improved the fatigue strength and reduced the anisotropy effect due to homogenized microstructure.