Microstructural characterization of TIG surface treating in Co-Cr-Mo-C alloy

Zangeneh, Sh.; Lashgari, H.R.; López, H. F.; Farahani, Hussein

doi:10.1016/j.matchar.2017.08.017

Cited by 13 publications

(7 citation statements)

References 17 publications

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“…Our previous studies [8,9] showed that quenching the Co-Cr-Mo alloy after solution treatment above 1100 • C promoted the formation of athermal ε martensite. It seems that the formation of high temperature defects which could act as potential sites for the nucleation of ε-martensite embryos is strongly favored at high cooling rates [21]. In addition, the high cooling rate generates internal residual stress resulting in the partial transformation of metastable fcc → hcp ε martensite.…”

Section: ≈70° ε Martensitementioning

confidence: 99%

“…The formation of athermal martensite mainly depends upon the solution temperature rather than the holding time at this temperature and in most cases the volume fraction of this phase does not exceed 20% [22]. This was attributed to the lack of enough defects necessary for spontaneous nucleation of ε martensite embryos during quenching [21]. For this reason, isothermal phase transformation is usually conducted at temperatures within the range of 650-950 • C to complete the γ fcc to ε hcp phase transformation.…”

Section: Isothermal Agingmentioning

confidence: 99%

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The Effect of Cyclic Solution Heat Treatment on the Martensitic Phase Transformation and Grain Refinement of Co-Cr-Mo Dental Alloy

Zangeneh

Lashgari

Alsaadi

et al. 2020

Metals

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The present study was undertaken to investigate the effect of continuous and discontinuous (cyclic) solution heat treatment on the athermal and isothermal ε martensite phase transformation in Co-28Cr-6Mo-0.3C implant alloy. The results showed that the cyclic solution heat treatment induced more of the athermal ε martensite phase in the alloy than that of the continues one. In addition, the cyclic heat treatment contributes to the development of more isothermal martensite phase during isothermal aging at 850 °C and, moreover, grain refinement in the area beneath the sample surface. The severity of grain refinement was highly significant adjacent to the surface and decreased by increasing the distance from the sample free surface. This novel grain refinement in high-carbon Co-Cr-Mo alloy was attributed to the generation of larger quenching thermal stresses introduced beneath the surface during cyclic solution treatment. The repetitive heating/cooling cycle modifies the surface properties, refines the grain size and leads to uniform dispersion of the secondary carbides. The corrosion resistance of the cyclically solution heat-treated samples was superior as compared to the as-cast one.

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Section: ≈70° ε Martensitementioning

confidence: 99%

Section: Isothermal Agingmentioning

confidence: 99%

The Effect of Cyclic Solution Heat Treatment on the Martensitic Phase Transformation and Grain Refinement of Co-Cr-Mo Dental Alloy

Zangeneh

Lashgari

Alsaadi

et al. 2020

Metals

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“…R. Rocha et al presented that Co-Cr alloys welded with TIG showed a higher flexural strength than Nd:YAG laser-welded and non-welded samples [ 25 ]. S. Zangeneh et al investigated the microstructural evolution of TIG-welded Co-28Cr-5Mo-0.3C alloy and concluded that the precipitation of M 23 C 6 carbides at the nanoscale leads to a significant increase in hardness [ 38 ]. M. Sahami-Nejad et al subjected the alloy Co-27Cr-5Mo-0.05C to TIG welding with different protective gas mixtures and investigated the microstructure, hardness and residual stress [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

Microscopic and Mechanical Characterization of Co-Cr Dental Alloys Joined by the TIG Welding Process

et al. 2023

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Due to their good mechanical and other properties, cobalt-chromium alloys (Co-Cr) are often used in prosthetic therapy. The metal structures of prosthetic works can be damaged and break, and depending on the extent of the damage, they can be re-joined. Tungsten inert gas welding (TIG) produces a high-quality weld with a composition very close to that of the base material. Therefore, in this work, six commercially available Co-Cr dental alloys were joined by TIG welding, and their mechanical properties were evaluated to determine the quality of the TIG process as a technology for joining metallic dental materials and the suitability of the Co-Cr alloys used for TIG welding. Microscopic observations were made for this purpose. Microhardness was measured using the Vickers method. The flexural strength was determined on a mechanical testing machine. The dynamic tests were carried out on a universal testing machine. The mechanical properties were determined for welded and non-welded specimens, and the results were statistically evaluated. The results show the correlation between the investigated mechanical properties and the process TIG. Indeed, characteristics of the welds have an effect on the measured properties. Considering all the results obtained, the TIG—welded I—BOND NF and Wisil M alloys showed the cleanest and most uniform weld and, accordingly, satisfactory mechanical properties, highlighting that they withstood the maximum number of cycles under dynamic load.

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“…Due to their excellent properties, such as strength, stiffness, wear resistance, biological properties and corrosion resistance, Co-Cr alloys are widely used in dentistry for the manufacture of removable partial denture frameworks. Corrosion resistance results from Cr-based oxides formed on the surface, which contribute to biocompatibility over time [2][3][4]. The wide use of Co-Cr alloys in dentistry is due to good mechanical properties and economic reasons, and it is still not easy to find an effective alternative [5].…”

Section: Introductionmentioning

confidence: 99%

“…By removing a new layer, the surface of the workpiece wears more and more so that corrosion can reach the deeper layers of the alloy [12][13][14][15]. However, due to pitting, crevice corrosion and uniform corrosion, Co-Cr alloys release ions when implanted in the human body and become harmful to the patient [3,4]. Metal ions are released from dental alloys because they are exposed daily to pH changes in the mouth, mechanical stress and damage, temperature fluctuations, contact with food and drink and contact with microorganisms.…”

Section: Introductionmentioning

confidence: 99%

Metal Ions Release from Welded Co—Cr Dental Alloys

2023

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Cobalt–chromium alloys (Co-Cr) are widely used in dentistry due to their excellent mechanical properties and corrosion resistance. Since prosthetic materials must be permanently stable in the oral cavity, it is very important to determine the release of ions from alloys in the oral cavity. In dentistry today, metals and alloys are mainly joined by laser and tungsten inert gas (TIG) welding. Therefore, in this work, the release of metal ions from six different Co-Cr alloys joined by these two welding methods was quantified to determine the effects of the welding method on an ion release. Static immersion tests, atomic absorption spectrometry and statistical analysis were performed for this purpose. The results showed that laser-welded alloys release a lower amount of metal ions compared to TIG-welded alloys.

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Microstructural characterization of TIG surface treating in Co-Cr-Mo-C alloy

Cited by 13 publications

References 17 publications

The Effect of Cyclic Solution Heat Treatment on the Martensitic Phase Transformation and Grain Refinement of Co-Cr-Mo Dental Alloy

The Effect of Cyclic Solution Heat Treatment on the Martensitic Phase Transformation and Grain Refinement of Co-Cr-Mo Dental Alloy

Microscopic and Mechanical Characterization of Co-Cr Dental Alloys Joined by the TIG Welding Process

Metal Ions Release from Welded Co—Cr Dental Alloys

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