FERREIRA, NELSON D.LEAL NETO, RICARDO M.FILGUEIRA, MARCELLOALVES, MANUEL F.R.P.SANTOS, CLAUDINEI dosRAMOS, ALFEU S.2021-02-242021-02-242020FERREIRA, NELSON D.; LEAL NETO, RICARDO M.; FILGUEIRA, MARCELLO; ALVES, MANUEL F.R.P.; SANTOS, CLAUDINEI dos; RAMOS, ALFEU S. Effect of cobalt doping and milling time on microstructure and Vickers microhardness of the spark plasma sintered (67-x)Ti-xCo-22Si-11B (x = 2 and 6 at-%) alloys. <b>Materials Research</b>, v. 23, n. 6, p. 1-10, 2020. DOI: <a href="https://dx.doi.org/10.1590/1980-5373-MR-2020-0337">10.1590/1980-5373-MR-2020-0337</a>. DisponÃvel em: http://repositorio.ipen.br/handle/123456789/31806.1516-1439http://repositorio.ipen.br/handle/123456789/31806Ti-6Al-4V and TiAl-based alloys are widely used for fabricating the implantable orthopedic devices and automotive components, respectively. Ti6Si2B-based alloys are attractive for use in orthopedic components because their higher hardness, superior biocompatibility and corrosion resistance in simulated body fluid than Ti and Ti-6Al-4V alloy. Limited information on Ti6Si2B stability in Co-dopped 67Ti-22Si-11B alloys are available in literature. This work presents the effect of cobalt doping and milling time on microstructure and Vickers microhardness of 65Ti-2Co-22Si-11B and 61Ti-6Co-22Si-11B (at-%) alloys produced by spark plasma sintering at 1100 oC for 12min using 20MPa. Samples were characterized by X ray diffraction, scanning electron microscopy, energy dispersive spectrometry, laser particle size analysis, and Vickers microhardness. Sintered alloys with 2 and 6at-%Co indicated the major presence of Ti6Si2B and Ti5Si3 dissolving up to 2.7 and 4.2 at-%Co, respectively, besides the minor precipitates of CoTi2 (4.4-16.7at-%Si) and CoTi (4.6-4.7at-%Si). Vickers microhardness of the sintered 65Ti-2Co-22Si-11B and 61Ti-6Co-22Si-11B alloys were in the range of 950-1050 and 1050-1150HV, respectively. Although the increase from 2 to 6at-%Co has reduced the Ti6Si2B stability, the Co-rich phases increased their hardness values up to 1150HV (11.3GPa), which are superior than those of commercial Ti alloys used for joint orthopedic components and automotive rotating parts.1-10openAccesscobaltcobalt hydroxidesdoped materialstitanium alloysimplantsmicrostructureplasmasinteringEffect of cobalt doping and milling time on microstructure and Vickers microhardness of the spark plasma sintered (67-x)Ti-xCo-22Si-11B (x = 2 and 6 at-%) alloysArtigo de periódico62310.1590/1980-5373-MR-2020-03370000-0001-5104-7392https://orcid.org/0000-0001-5104-739216.6750.25