The metallography of a cobalt-based implant alloy after solution treatment and ageing

Taylor, R N; Waterhouse, R.B.

doi:10.1007/bf00547938

Cited by 23 publications

(18 citation statements)

References 9 publications

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“…From these results, c was estimated to be 54 mJ/m 2 , by considering a shear modulus of 30 GPa. The estimated c value is higher than the one reported by Taylor et al (c = 16 mJ/m 2 [20] ), yet not appreciably high when considering other stacking fault energies where splitting of lattice dislocations is observed (c Zn = 300 mJ/m 2 or c Cd = 175 mJ/m 2 [42] ). Hence, it is expected that as the actual c increases, the fcc fi hcp transformation becomes increasingly sluggish or even stops taking place beyond a critical c value.…”

Section: E Segregation Effects On Cmentioning

confidence: 43%

“…Hence, it is expected that as the actual c increases, the fcc fi hcp transformation becomes increasingly sluggish or even stops taking place beyond a critical c value. Hence, a c value of 54 mJ/m 2 would correspond to a region where the fcc fi hcp transformation rate is relatively slow, with rates well below the ones measured by Taylor et al [20] Accordingly, in cast Co-base alloys, it is expected that the hcp transformation would be relatively slow depending on the local c, particularly in regions where platelike martensite is the dominant mode of growth (zone 2, Figure 6). …”

Section: E Segregation Effects On Cmentioning

confidence: 93%

“…[31] In the investigated cast Co alloy, lamellae morphologies were not common, discarding the possibility of discontinuous cellular reactions as being the dominant transformation mechanism, as suggested by some authors. [20,31] …”

Section: Isothermal Transformationmentioning

confidence: 98%

“…Taylor and Waterhouse [20] found that M 23 C 6 -type carbides are the dominant carbides in cast cobalt alloys of similar compositions. Estimates of the extent of coring across dendrites by EDX indicated that Cr and Mo exhibited the highest extent of segregation ( Figure 2).…”

Section: A As-received Alloymentioning

confidence: 98%

“…In this case, the main barrier for carbide growth is related to the actual coherency strains at the hcp/carbide interphase. Taylor and Waterhouse [20] have found that the M 23 C 6 carbides, which are fcc type with a lattice parameter similar to fcc Co, are the typical carbides developed, accounting for minimal coherency strains.…”

Section: E Segregation Effects On Cmentioning

confidence: 98%

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Martensitic Transformation in a Cast Co-Cr-Mo-C Alloy

López

Saldívar-García²

2007

Metall Mater Trans A

113

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The face-centered-cubic (fcc) to hexagonal close-packed (hcp) martensitic transformation exhibited by an as-cast Co-Cr-Mo-C alloy was investigated in this work. The alloy was annealed at 1150°C, water quenched, and then isothermally aged at 700°C to 900°C. Quantitative measurements of transformed hcp martensite (also known as e-martensite) as a function of time and temperature were used in plotting C curves describing the transformation kinetics. Moreover, microstructural characterization indicated that the transformation exhibited two distinctive e-martensite morphologies. In the neighborhood of coarse carbides, multiple nucleation events were linked to the formation of e-martensite, while in the bulk of the dendrite matrix, the dominant morphology was as straight plates. Kinetic determinations of activation energies, Q, in either region indicated that in platelike e-martensite, Q = 57.24 kcal/mol, but in ''pearlite''-like morphologies, Q = 37.88 kcal/mol. Apparently, as the activation energy was reduced, multiple nucleation events were favored leading to the ''pearlitic'' appearance.

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Section: E Segregation Effects On Cmentioning

confidence: 43%

Section: E Segregation Effects On Cmentioning

confidence: 93%

Section: Isothermal Transformationmentioning

confidence: 98%

Section: A As-received Alloymentioning

confidence: 98%

Section: E Segregation Effects On Cmentioning

confidence: 98%

See 3 more Smart Citations

Martensitic Transformation in a Cast Co-Cr-Mo-C Alloy

López

Saldívar-García²

2007

Metall Mater Trans A

113

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Microstructural effects on the wear resistance of wrought and as‐cast Co‐Cr‐Mo‐C implant alloys

Saldívar-García

López

2005

J Biomedical Materials Res

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The tribological behavior of two cobalt-base alloys-an as-cast high-carbon and a wrought low-carbon Co alloy-that are used as hip implant materials is examined in this work. This work discusses the experimental results of cobalt-cobalt wear pairs, in wrought and as-cast conditions, where the amount of hexagonal phase is systematically modified through an isothermal aging treatment. Fully FCC and HCP Co alloys are tested versus alloys with various volume fractions of HCP phase (0.05 to 1.0 volume fractions). Preliminary results indicate that Co-Cr-Mo/Co-Cr-Mo alloy pairs both possessing an HCP matrix microstructure tend to exhibit outstanding wear properties.

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Effects of alloy additions on the microstructures and tensile properties of cast Co-Cr-Mo alloy used for surgical implants

Zhuang

Langer

1989

J Mater Sci

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The metallography of a cobalt-based implant alloy after solution treatment and ageing

Cited by 23 publications

References 9 publications

Martensitic Transformation in a Cast Co-Cr-Mo-C Alloy

Martensitic Transformation in a Cast Co-Cr-Mo-C Alloy

Microstructural effects on the wear resistance of wrought and as‐cast Co‐Cr‐Mo‐C implant alloys

Effects of alloy additions on the microstructures and tensile properties of cast Co-Cr-Mo alloy used for surgical implants

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