Atom scale study of cracks in the carbide phase of WC–Co alloys

Fe-Cr-Co alloys have great technological potential to replace Alnico alloys as hard magnets. The relationship between the microstructures and the magnetic properties has been recently established for some of these alloys. The magnetic hardening has been attributed to the decomposition of the high temperature stable phase (α) into an elongated Fe-rich ferromagnetic phase (α1) and a weakly magnetic or non-magnetic Cr-rich phase (α2). The relationships between magnetic domains and domain walls and these different phases are yet to be understood. The TEM has been used to ascertain the mechanism of magnetic hardening for the first time in these alloys. The present paper describes the magnetic domain structure and the magnetization reversal processes in some of these multiphase materials. Microstructures to change properties resulting from, (i) isothermal aging, (ii) thermomagnetic treatment (TMT) and (iii) TMT + stepaging have been chosen for this investigation. The Jem-7A and Philips EM-301 transmission electron microscopes operating at 100 kV have been used for the Lorentz microscopy study of the magnetic domains and their interactions with the finely dispersed precipitate phases.

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An atomic resolution study of a carbide phase in platinum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120503 ◽

1992 ◽

Vol 50 (1) ◽

pp. 20-21

Author(s):

M.J. Witcomb ◽

M.A. O'Keefe ◽

CJ. Echer ◽

C. Nelson ◽

J.H. Turner ◽

...

Keyword(s):

Solid Solution ◽

Carbon Atom ◽

Carbide Phase ◽

Structural Changes ◽

Critical Role ◽

Alloy System ◽

Atomic Resolution ◽

Excess Carbon ◽

Interstitial Carbon ◽

Resolution Study

Under normal circumstances, Pt dissolves only a very small amount of interstitial carbon in solid solution. Even so, an appropriate quench/age treatment leads to the formation of stable Pt2C {100} plate precipitates. Excess (quenched-in) vacancies play a critical role in the process by accommodating the volume and structural changes that accompany the transformation. This alloy system exhibits other interesting properties. Due to a large vacancy/carbon atom binding energy, Pt can absorb excess carbon at high temperatures in a carburizing atmosphere. In regions rich in carbon and vacancies, another carbide phase, Pt7C which undergoes an order-disorder reaction was formed. The present study of Pt carburized at 1160°C and aged at 515°C shows that other carbides in the PtxC series can be produced.

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TEM INVESTIGATIONS OF WC-Co ALLOYS AFTER CREEP EXPERIMENTS

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19861105 ◽

1986 ◽

Vol 47 (C1) ◽

pp. C1-685-C1-689 ◽

Cited By ~ 1

Author(s):

S. LAY ◽

F. OSTERSTOCK ◽

J. VICENS

Keyword(s):

Co Alloys

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The effect of HCP on the formation of twin boundaries and dislocations in Ni–Co alloys

Current Applied Physics ◽

10.1016/j.cap.2021.05.012 ◽

2021 ◽

Vol 29 ◽

pp. 18-23

Author(s):

Rui-bo Ma ◽

Li-li Zhou ◽

Yong-chao Liang ◽

Qian Chen ◽

Ze-an Tian ◽

...

Keyword(s):

Twin Boundaries ◽

Co Alloys

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Effect of the Ni content on the thermal and magnetic properties of Fe–Ni–Co alloys

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2020.124215 ◽

2021 ◽

Vol 261 ◽

pp. 124215

Author(s):

A. Paganotti ◽

C.V.X. Bessa ◽

C.C.S. Silva ◽

E.B. Peixoto ◽

J.G.S. Duque ◽

...

Keyword(s):

Magnetic Properties ◽

Ni Content ◽

Co Alloys

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New Electrodes Based on Pt-Co Alloys Used as Anodic Materials for Sulphite Oxidation in Alkaline Fuel Cells

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/416/1/012072 ◽

2018 ◽

Vol 416 ◽

pp. 012072

Author(s):

A F Enache ◽

M L Dan ◽

R Muntean ◽

N Vaszilcsin

Keyword(s):

Fuel Cells ◽

Alkaline Fuel Cells ◽

Co Alloys

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Short and Medium-Range Order in Liquid Ternary Al80Co10Ni10, Al72.5Co14.5Ni13, and Al65Co17.5Ni17.5 Alloys

Zeitschrift für Naturforschung A ◽

10.1515/zna-2010-1-214 ◽

2010 ◽

Vol 65 (1-2) ◽

pp. 123-131 ◽

Cited By ~ 2

Author(s):

Oleksandr S. Roik ◽

Oleksiy Samsonnikov ◽

Volodymyr Kazimirov ◽

Volodymyr Sokolskii

Keyword(s):

Three Dimensional ◽

Range Order ◽

Ternary Alloys ◽

X Ray Diffraction ◽

Medium Range Order ◽

Intermediate Range Order ◽

Transition Metal Atoms ◽

Medium Range ◽

Three Dimensional Models ◽

Co Alloys

AbstractA local short-to-intermediate range order of liquid Al80Co10Ni10, Al72.5Co14.5Ni13, and Al65Co17.5Ni17.5 alloys was examined by X-ray diffraction and the reverse Monte Carlo modelling. The comprehensive analysis of three-dimensional models of the liquid ternary alloys was performed by means of the Voronoi-Delaunay method. The existence of a prepeak on the S(Q) function of the liquid alloys is caused by medium range ordering of 3d-transition metal atoms in dense-packed polytetrahedral clusters at temperatures close to the liquidus. The non-crystalline clusters, represented by aggregates of pentagons that consist of good tetrahedra, and chemical short-range order lead to the formation of the medium range order in the liquid binary Al-Ni, Al-Co and ternary Al-Ni-Co alloys.

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