Effect of heat treatment on the microstructure and fatigue strength of CoCrMo alloys fabricated by selective laser melting

Seki, Erina; Kajima, Yuka; Takaichi, Atsushi; Kittikundecha, Nuttaphon; Cho, Hla Htoot Wai; Htat, Hein Linn; Doi, Hisashi; Hanawa, Takao; Wakabayashi, Noriyuki

doi:10.1016/j.matlet.2019.02.085

Cited by 42 publications

(9 citation statements)

References 7 publications

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“…The crystal orientations of CCM fibers were completely different from those of CCM alloys made by casting and selective laser melting, which were composed of grains with random crystal orientations. [40,41] Figure 7b shows the IPF maps in the X-direction for CCM2 [2], CCM2 [5], CCM2 [10], CCM1 [2], CCM1 [5], and CCM1 [10] fibers. The crystal orientation of each grain became random with increasing growth rate, confirming that there was insufficient time to align the grains at a faster growth rate.…”

Section: Microstructure Of Ccm Crystal Fibermentioning

confidence: 99%

Growth, Microstructure, and Mechanical Properties of Co–Cr–Mo Crystal Fibers Fabricated from the Melt by Unidirectional Solidification

et al. 2021

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Many complicated forming processes are required to fabricate thin wires of Co–Cr–Mo (CCM) biomedical materials due to the poor workability of these materials. A novel fabrication technique for CCM crystal fibers is developed by unidirectional solidification directly from the melt using the alloy‐micro‐pulling‐down (A‐μ‐PD) method. Compared with conventional methods, the proposed technique is an innovative fabrication method for CCM alloy fibers and is characterized by low cost, time saving, and low loading. In addition, the proposed method shows potential for further thinning of fibers. At growth rates of 0.1 and 0.3 mm min−1, CCM single‐crystal fibers composed of the ε‐phase with a hexagonal close‐packed (hcp) structure (hcp ε‐phase) can be fabricated. The hcp‐ε‐phase CCM crystal fibers exhibit considerably improved strain because of the slipping line in the hcp structure. Moreover, the γ‐phase with an fcc structure (fcc γ‐phase) appears in the hcp‐ε‐phase at growth rates greater than 0.5 mm min−1, and the ratio of the fcc γ‐phase in the CCM crystal fibers systematically increases with an increase in the cooling rate. The results reveal that the growth rate in the A‐μ‐PD method has a notable effect on the fabrication of single‐ or polycrystalline CCM fibers.

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Section: Microstructure Of Ccm Crystal Fibermentioning

confidence: 99%

Growth, Microstructure, and Mechanical Properties of Co–Cr–Mo Crystal Fibers Fabricated from the Melt by Unidirectional Solidification

et al. 2021

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“…Anisotropic columnar grains, dendritic structures, and sub-grains for samples with all build angles were transformed into uniform equiaxed grains with no apparent internal disorientation. The residual strain inside the grains was relieved [ 63 ] as a result of thermally induced recrystallization, which is likely driven by the strain energy stored in the microstructure by differential thermal contractions during the PBF process [ 65 , 66 ]. High dislocation densities are present at the boundaries of the cellular dendritic structures, observed in the finished PBF products, which result in stored energy in these regions.…”

Section: Post-processing Strategiesmentioning

confidence: 99%

“…Considering the characteristics of loads that occur in the oral environment, one of the key properties of prosthetic components is fatigue resistance. The fatigue strength of SLM samples was improved after heat treatment at 1150 °C [ 63 ]. However, in one study, controls with 90° building angulations exhibited longer fatigue life than the heat-treated groups [ 45 ].…”

Section: Post-processing Strategiesmentioning

confidence: 99%

“…Six hours heat treatment created large precipitates and a thick oxide layer associated with a decrease in fatigue strength. [45,63] It was shown that the heat treatment up to 1050 • C for six hours was insufficient to eliminate anisotropy and residual stress. However, the dendritic structures and number of sub-grains decreased while increasing the heat-treatment temperature (from 750 • C to 1050 • C) compared with the as-built samples [60].…”

Section: Stress Relievingmentioning

confidence: 99%

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Challenges of Co–Cr Alloy Additive Manufacturing Methods in Dentistry—The Current State of Knowledge (Systematic Review)

et al. 2020

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Complex dental components which are individually tailored to the patient can be obtained due to new additive manufacturing technology. This paper reviews the metallic powders used in dental applications, the fabrication process (build orientation, process parameters) and post-processing processes (stress relieving, surface finishing). A review of the literature was performed using PubMed, ScienceDirect, Mendeley and Google Scholar. Over eighty articles were selected based on relevance to this review. This paper attempts to include the latest research from 2010 until 2020, however, older manuscripts (10 articles) were also selected. Over 1200 records were identified through the search; these were screened for title and/or summary. Over eighty articles were selected based on relevance to this review. In order to obtain a product which can be used in clinical applications, the appropriate manufacturing parameters should be selected. A discussion was made on optimal selective laser melting (SLM) parameters in dentistry. In addition, this paper includes a critical review of applied thermal treatment methods for Co–Cr alloys used in dentistry.

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“…Co bazlı alaşımlar yüksek yorulma dayanımı, aşınma ve korozyon direnci gibi özellikler gösterir. CoCrMo alaşımları, plastik parçaların enjeksiyonla kalıplanması için aletlerin imalatında, hava ve karada çalışan gaz türbinlerinin (yük taşıma, valfler, valf yuvaları ve burçlar manşonlarının) performansında ve çoğunlukla yapay kalça eklemlerinde, diş protezlerinde ve diz eklemleri gibi uygulamalarda kullanılmaktadır [10][11][12][13]. CoCrMo alaşımlarında nitrürleme, karbürleme ve sertleştirme gibi yüzey işlemlerinin uygulanması aşınma ve korozyon direncini arttırmaktadır [14][15][16].…”

Section: Introductionunclassified

%3 Mg içeren Borlanmış Co-Mg Alaşımının Yüzey Özelliklerinin İncelenmesi

Yildiz

Güneş

2019

El-Cezeri Fen Ve Mühendislik Dergisi

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Bu çalışmada, %97 Co ve %3 Mg içeren Co-Mg alaşımına borlama işlemi gerçekleştirilmiştir. Co-Mg alaşım malzemesini üretmek için toz metalurjisi (TM) yöntemi kullanılmıştır. Bu yöntemde, Co ve Mg metal tozları kapalı kaplar içerisinde homojen bir şekilde karıştırılarak şekillendirilmeleri için özel olarak tasarlanmış silindirik kalıplara dökülmüştür. Tek eksenli preste 300 bar basınç altında preslendikten sonra Argon gazı atmosferi ortamında 530 °C sıcaklıkta sinterlenmiştir. Sinterlenerek üretilen numunelere sırasıyla sertlik, yoğunluk ve yüzey pürüzlülüğü testleri uygulanmıştır. Sertlik testi sonrası 123 HV 0,05 değeri elde edilirken ölçülen yoğunluk değeri ise 4,95 gr/cm 3 olarak bulunmuştur. Bu işlemler sonrasında numuneler kapalı fırın ortamında 850 ve 900 °C sıcaklık ve 1.5-4.5 saat değişen sürelerde borlama işlemi gerçekleştirilmiştir. Bu işlem sonrasında SEM ve XRD analiz çalışmaları yapılmıştır. Analiz sonrasında borür tabakaları 850 °C sıcaklıkta 1,5 saat sürede 55 µm olarak bulunurken en yüksek 900 °C sıcaklık 4,5 saat sürede 140 µm olarak ölçülmüştür. Borlanmış Kobalt-Magnezyum alaşımlarına uygulanan XRD analizi sonucunda CoB, Co 2 B ve Co fazları elde edilmiştir. Mg elementinin hızlı bozulma özelliğinden dolayı yapılarda kısmende olsa boşluklar oluşmuştur.

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Effect of heat treatment on the microstructure and fatigue strength of CoCrMo alloys fabricated by selective laser melting

Cited by 42 publications

References 7 publications

Growth, Microstructure, and Mechanical Properties of Co–Cr–Mo Crystal Fibers Fabricated from the Melt by Unidirectional Solidification

Growth, Microstructure, and Mechanical Properties of Co–Cr–Mo Crystal Fibers Fabricated from the Melt by Unidirectional Solidification

Challenges of Co–Cr Alloy Additive Manufacturing Methods in Dentistry—The Current State of Knowledge (Systematic Review)

%3 Mg içeren Borlanmış Co-Mg Alaşımının Yüzey Özelliklerinin İncelenmesi

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