检索结果-南通市图书馆

Rare Metals 2005年第1期24卷 76-81页

作者： HOUQingyu GAOJiasheng SchoolofMaterialsScience＆Engineering AnhuiUniversityofTechnologyMa＇anshan243002China SchoolofMaterialsScience＆Engineering AnhuiUniversityofTechnologyMa＇anshan243002China

The microstructure, substructure, and wear characteristic of cobalt-basedalloy coatings obtained by plasma transferred arc (PTA) process were investigated using opticalmetallurgical microscope, X-ray diffraction (XRD), scanning electron microscope (SEM), transmissionelectron microscope (TEM), and dry sand abrasion tester (DSAT). The aging effect on the structureand wear resistance of the cobalt-based PTA coating was also studied. The results show that theas-welded coating consists of cobalt-based solid solution with face-centered cubic structure andhexagonal (Cr,Fe)_7C_3. There are a lot of stacking faults existing in the cobalt-based solidsolution. After aging at 600 deg C for 60 h, the microstructure becomes coarse, and another carbide(Cr,Fe)_(23)C_6 precipitates. As a result, the wear mass loss of the aged sample is higher than thatof the as-welded sample.

关键词： cobalt-based alloy plasma transferred arc (PTA) microstructure wear

Effects of Y_2O_3 on the microstructure and wear resistance of cobalt-based alloy coatings deposited by plasma transferred arc process

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2007年第2期26卷 103-109页

作者： HOU Qingyu HUANG Zhenyi GAO Jiasheng Anhui Key Laboratory of Metal Materials and Processing School of Materials Science and Engineering Anhui University of Technology Ma＇anshan 243002 China

cobalt-based alloys with different Y2O3 contents were deposited on Q235A-carbon steel using plasma transferred arc （PTA） welding machine. The effect of Y2O3 on the microstructure and wear resistance properties of the cobait-based alloys were investigated using an optical microscope, a scanning electron microscope （SEM）, X-ray diffraction （XRD）, and transmission electron microscopy （TEM）. It was found that a cobalt-based solid solution with a face-centered cubic crystal structure was presented accompanied by the secondary phase M7C3 with a hexagonal crystal structure in the Y2O3-free cobalt-based alloy coating. Several stacking faults exist in the cobalt-based solid solution. The addition of Y2O3 leads to the existence of the Y2O3 phase in the Y2O3-modified coatings. Though stacking fault exists in the Y2O3-modified coatings, its density increases. The addition of Y2O3 can refine the microstructure and can increase the wear resistance properties when its contents are less than or equal to 0.8 wt.%. However, further increase of its contents will lead to the agglomeration of undissolved Y2O3 particles at the γ-Co grain boundary, and will lead to a coarse microstructure and lower wear resistance properties.

关键词： cobalt-based alloy plasma transferred arc (PTA) Y2O3 microstructure wear resistance

Lifecycle of cobalt-based alloy for artificial joints:From bulk material to nanoparticles and ions due to bio-tribocorrosion

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第11期42卷 98-106页

作者： Zhongwei Wang Yu Yan Yang Wang Yanjing Su Lijie Qiao Beijing Advanced Innovation Center for Materials Genome Engineering Corrosion and Protection CenterKey Laboratory for Environmental Fracture(MOE)University of Science and Technology BeijingBeijing 100083China College of Materials Science and Engineering Chongqing University of TechnologyChongqing 400054China Corrosion and Protection Center Advanced Institute for Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China

The release of debris and ions from metallic artificial joints during bio-tribocorrosion posed a severe threat to patient *** this work,the lifecycle of a Co Cr Mo alloy was presented by investigating the subsurface microstructure transformation *** results showed that the originally coarse grains changed to nano-grains(NGs)on the top region of the alloy,and nanoparticles(NPs)were torn off the surface,which were then blocked by the *** agglomerated alloy NPs contained in the tribofilm transformed into debris after being removed from the alloy *** majority of the torn-off NPs were corroded and released ions into solution due to their high chemical activities.

关键词： cobalt-based alloy Artificial joints Wear mechanism Bio-t Ribocorrosion TEM

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第16期111卷 99-110页

作者： Vioni Dwi Sartika Won Seok Choi Gwanghyo Choi Jaewook Han Sung-Jin Chang Won-Seok Ko Blazej Grabowski Pyuck-Pa Choi Department of Materials Science and Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea Gangwon Regional Division Korea Institute of Industrial TechnologyGangwon 25440Republic of Korea Division of Measurement and Analysis National Nanofab CenterDaejeon 34141Republic of Korea School of Materials Science and Engineering University of UlsanUlsan 44610Republic of Korea Institute for Materials Science University of StuttgartPfaffenwaldring 5570569 StuttgartGermany

We report laser cladding of pure titanium on a CoCrMo alloy using directed energy *** electron microscopy,the microstructural evolution upon varying the process parameters,especially laser power and powder feed rate,was investigated in relation to crack *** layers showing dilution rates of more than 5%contained cracks due to the formation of the brittle Co_(2)Ti intermetallic *** observed cracks could be ascribed to a mismatch in thermal expansion and a resulting stress of more than 440 MPa acting on the Co_(2)Ti phase,as determined by density functional theory and ***,an excess laser energy caused chemical inhomogeneity and unmelted Ti powder particles,while a deficient laser energy resulted in a lack of *** cracks nor partially melted powders were observed for a powder feed rate of 3 g/min and a laser power of 225–300 W,for which the dilution rate was minimized to less than 5%.For such samples,the cladding layers comprised pureα-Ti and a uniform CoT i interface with Co_(2)Ti islands.

关键词： Additive manufacturing Dissimilar metal joining Titanium cobalt-based alloy

In vitro Evaluation with 5SBF of alloy ASTM F75 Thermally Treated with Wollastonite

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2016年第3期31卷 487-490页

作者： MUNIZ Rodrigo ORTIZ Juan LUNA Jesus MARTINEZ Jesus RODRIGEZ Nelly HERNANDEZ Marco OROZCO Pilar EQUIHUA Fabian Faculty of Engineering Autonomous University of CoahuilaCUSaltilloMexico Department of Metal Mechanics Technological Institute of SaltilloMexico Faculty of Engineering Mechanical and Electrical Autonomous University of Nuevo LeonMexico Faculty of Engineering Autonomous University of Zacatecas Faculty of Mechanical and Electrical Engineering Autonomous University of Coahuila North UnitMonclovaMexico

Samples of a cobalt-based alloy that underwent a surface treatment were evaluated. The samples, which were obtained by casting alloy ASTM F 75, were ground and polished on one side until a mirror finish was obtained. The samples were encapsulated in wollastonite （W） using uniaxial pressure, treated at 1 220 ~C for 1 h and subsequently tempered in water. The characterisation of the sample indicated that part of the ceramic encapsulating material was mechanically incorporated on the metallic surface by growth of the oxide layer of the alloy. After thermal treatment, a series of specimens were submerged in a solution with 5-fold simulated body fluid （5SBF） for 3, 5 and 21 days. Characterisation by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD） indicated nucleation and growth of a homogenous layer of apatite, beginning on the third day when the sample was submerged.

关键词： cobalt-based alloy wollastonite 5SBF apatite.