title: Effects of thermal treatments on microstructure and mechanical properties of a Co-Cr-Mo-W biomedical alloy produced by laser sintering.
abstract: Direct Metal Laser Sintering (DMLS) technology based on a layer by layer production process was used to produce a Co-Cr-Mo-W alloy specifically developed for biomedical applications. The alloy mechanical response and microstructure were investigated in the as-sintered state and after post-production thermal treatments. Roughness and hardness measurements, and tensile and flexural tests were performed to study the mechanical response of the alloy while X-ray diffraction (XRD), electron microscopy (SEM, TEM, STEM) techniques and microanalysis (EDX) were used to investigate the microstructure in different conditions. Results showed an intricate network of ε-Co (hcp) lamellae in the γ-Co (fcc) matrix responsible of the high UTS and hardness values in the as-sintered state. Thermal treatments increase volume fraction of the ε-Co (hcp) martensite but slightly modify the average size of the lamellar structure. Nevertheless, thermal treatments are capable of producing a sensible increase in UTS and hardness and a strong reduction in ductility. These latter effects were mainly attributed to the massive precipitation of an hcp Co3(Mo,W)2Si phase and the contemporary formation of Si-rich inclusions.
authors.affiliation: Dipartimento SIMAU, Università Politecnica delle Marche, 60131 Ancona, Italy. Electronic address: p.mengucci@univpm.it.
authors.forename: P
authors.initials: P
authors.lastname: Mengucci
authors.affiliation: Dipartimento SIMAU, Università Politecnica delle Marche, 60131 Ancona, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Barucca
authors.affiliation: Dipartimento DIEF, Università di Modena e Reggio Emilia, Via Vivarelli 10, 41125 Modena, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Gatto
authors.affiliation: Dipartimento DIEF, Università di Modena e Reggio Emilia, Via Vivarelli 10, 41125 Modena, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Bassoli
authors.affiliation: Dipartimento DIEF, Università di Modena e Reggio Emilia, Via Vivarelli 10, 41125 Modena, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Denti
authors.affiliation: Dipartimento DISCO, Università Politecnica delle Marche, 60131 Ancona, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Fiori
authors.affiliation: Dipartimento DISCO, Università Politecnica delle Marche, 60131 Ancona, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Girardin
authors.affiliation: Dipartimento SIMAU, Università Politecnica delle Marche, 60131 Ancona, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Bastianoni
authors.affiliation: International Centre of Electron Microscopy for Material Science & Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, Al. A. Mickiewicza 30, 30-059 Kraków, Poland.
authors.forename: B
authors.initials: B
authors.lastname: Rutkowski
authors.affiliation: International Centre of Electron Microscopy for Material Science & Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, Al. A. Mickiewicza 30, 30-059 Kraków, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Czyrska-Filemonowicz
mesh_terms: D000497:Alloys; D001672:Biocompatible Materials; D002857:Chromium; D003035:Cobalt; D006244:Hardness; D006358:Hot Temperature; D007834:Lasers; D008982:Molybdenum; D013718:Tensile Strength; D014414:Tungsten; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D002857:Chromium; D003035:Cobalt; D008982:Molybdenum; D014414:Tungsten
keywords: Co alloys; Heat treatments; Laser sintering; Mechanical properties; Structure characterisation