Effect of phase transformation on ductility of additively manufactured Co–28Cr–6Mo alloy: An in situ synchrotron X-ray diffraction study during mechanical testing

Antunes, Luiz Henrique Martinez; Hoyos, John Jairo; Fonseca, Eduardo Bertoni da; Béreš, Miloslav; Farina, Paula Fernanda da Silva; Lopes, Éder Sócrates Najar; Jardini, André Luiz; Filho, Rubens Maciel

doi:10.1016/j.msea.2019.138262

Cited by 27 publications

(17 citation statements)

References 36 publications

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“…The as-built material composition ( Table 2 ) is in accordance with the manufacturer’s material datasheet (EOS GmbH—Electro Optical Systems) and with the specifications to be used as a surgical implant (ASTM F75-12). Microstructures composed of cellular dendrites are formed during the SLM building process ( Figure 3 B,C), where the molten material is submitted to high cooling rates and non-equilibrium structures are obtained [ 24 , 42 ]. It is possible to verify the nanostructures anodized by the PIII surfaces ( Figure 3 D,E).…”

Section: Resultsmentioning

confidence: 99%

“…The surface of the material is essential for osseointegration [ 24 , 44 , 47 , 75 ]. Within this concept, the production of metal alloys with micro-roughness on the surface (1 to 10 µm) can be done by sandblasting, acid attack, plasma spray and other technical modification surfaces [ 76 , 77 , 78 , 79 ], as well as by AM, which in turn allows design control, customized porosity and roughness [ 80 , 81 ].…”

Section: Discussionmentioning

confidence: 99%

“…However, all the alloys used had satisfactory results in stimulating bone formation when considering that the bone volume formed in the groups with metallic implants (G2, G3, G4) was higher than that found in the G1 control group. Thus, although the Co-Cr-Ti alloy has shown better results for bone repair, it must be considered that all metal alloys used in the present research, and which were manufactured by additive manufacturing, may receive attention in new studies of bioengineering applied in regeneration experimental bone [ 24 , 42 ].…”

Section: Discussionmentioning

confidence: 99%

“…However, Co-Cr-Mo alloys are hard to process by machining, which limits its production for casting techniques. In this context, additive manufacturing (AM), a layer-by-layer production technique, can be used to produce Co-Cr-Mo alloy implants [ 24 ]. Due to the nearly unlimited geometrical freedom, this technique can be employed to produce customized implants with complex geometries, considering the patient’s physical and anatomic characteristics, as well as the shape and size of the bone lesion.…”

Section: Introductionmentioning

confidence: 99%

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Osseointegration Improvement of Co-Cr-Mo Alloy Produced by Additive Manufacturing

et al. 2021

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Cobalt-base alloys (Co-Cr-Mo) are widely employed in dentistry and orthopedic implants due to their biocompatibility, high mechanical strength and wear resistance. The osseointegration of implants can be improved by surface modification techniques. However, complex geometries obtained by additive manufacturing (AM) limits the efficiency of mechanical-based surface modification techniques. Therefore, plasma immersion ion implantation (PIII) is the best alternative, creating nanotopography even in complex structures. In the present study, we report the osseointegration results in three conditions of the additively manufactured Co-Cr-Mo alloy: (i) as-built, (ii) after PIII, and (iii) coated with titanium (Ti) followed by PIII. The metallic samples were designed with a solid half and a porous half to observe the bone ingrowth in different surfaces. Our results revealed that all conditions presented cortical bone formation. The titanium-coated sample exhibited the best biomechanical results, which was attributed to the higher bone ingrowth percentage with almost all medullary canals filled with neoformed bone and the pores of the implant filled and surrounded by bone ingrowth. It was concluded that the metal alloys produced for AM are biocompatible and stimulate bone neoformation, especially when the Co-28Cr-6Mo alloy with a Ti-coated surface, nanostructured and anodized by PIII is used, whose technology has been shown to increase the osseointegration capacity of this implant.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Osseointegration Improvement of Co-Cr-Mo Alloy Produced by Additive Manufacturing

et al. 2021

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“…In literature, the reported contents of hcp phase in the SLMed CCM alloy vary significantly among different authors. Many of the works [18,56,57] detected only fcc Co-phase, which they attribute to high cooling rates during SLM. However, other works [9,44,50] have reported a certain content of hcp phase as we did.…”

Section: Initial Microstructurementioning

confidence: 99%

Different Response of Cast and 3D-Printed Co-Cr-Mo Alloy to Heat Treatment: A Thorough Microstructure Characterization

Roudnická

Bigas

Molnárová

et al. 2021

Metals

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The Co-Cr-Mo alloy is a biomaterial with very good corrosion resistance and wear resistance; thus, it is widely applied for knee replacements. The wear resistance is influenced by the amount of hcp phase and morphology of carbidic precipitates, which can both be altered by heat treatment. This study compares a conventional knee replacement manufactured by investment casting with a material prepared by the progressive technology of 3D printing. The first set of results shows a different response of both materials in increasing hardness with annealing at increasing temperatures up to the transformation temperature. Based on these results, solution treatment and subsequent aging at conditions to reach the maximum hardness was applied. Microstructural changes were studied thoroughly by means of optical, scanning electron and transmission electron microscopy. While increased hardness in the conventional material is caused by the precipitation of fine hard carbides combined with an increase in the hcp phase by isothermal transformation, a massive fcc → hcp transformation is the main cause for the hardness increase in the 3D-printed material.

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Co–Cr–Mo alloy fabricated by laser powder bed fusion process: grain structure, defect formation, and mechanical properties

Costa

Oliveira

Munhoz

et al. 2021

Int J Adv Manuf Technol

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Effect of phase transformation on ductility of additively manufactured Co–28Cr–6Mo alloy: An in situ synchrotron X-ray diffraction study during mechanical testing

Cited by 27 publications

References 36 publications

Osseointegration Improvement of Co-Cr-Mo Alloy Produced by Additive Manufacturing

Osseointegration Improvement of Co-Cr-Mo Alloy Produced by Additive Manufacturing

Different Response of Cast and 3D-Printed Co-Cr-Mo Alloy to Heat Treatment: A Thorough Microstructure Characterization

Co–Cr–Mo alloy fabricated by laser powder bed fusion process: grain structure, defect formation, and mechanical properties

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