Cobalt mechanical properties

Table 13 is a representative Hst of nickel and cobalt-base eutectics for which mechanical properties data are available. In most eutectics the matrix phase is ductile and the reinforcement is britde or semibritde, but this is not invariably so. The strongest of the aHoys Hsted in Table 13 exhibit ultimate tensile strengths of 1300—1550 MPa. Appreciable ductiHty can be attained in many fibrous eutectics even when the fibers themselves are quite britde. However, some lamellar eutectics, notably y/y —5, reveal Htde plastic deformation prior to fracture. 

Many different values for room temperature mechanical properties can be found in the Hterature. The lack of agreement depends, no doubt, on the different mixtures of a and y phases of cobalt present in the material. This, on the other hand, depends on the impurities present, the method of production of the cobalt, and the treatment. 

Mechanical properties depend on the alloying elements. Addition of carbon to the cobalt base metal is the most effective. The carbon forms various carbide phases with the cobalt and the other alloying elements (see Carbides). The presence of carbide particles is controlled in part by such alloying elements such as chromium, nickel, titanium, manganese, tungsten, and molybdenum that are added during melting. The distribution of the carbide particles is controlled by heat treatment of the solidified alloy. 

Stacking faults thereby providing barriers to sHp. If carbides are allowed to precipitate to the point of becoming continuous along the grain boundaries, they often initiate fracture (see Fracture mechanics). A thorough discussion of the mechanical properties of cobalt alloys is given in References 29 and 30 (see also Refractories). 

Edwards e/a/. carried out controlled potential, slow strain-rate tests on Zimaloy (a cobalt-chromium-molybdenum implant alloy) in Ringer s solution at 37°C and showed that hydrogen absorption may degrade the mechanical properties of the alloy. Potentials were controlled so that the tensile sample was either cathodic or anodic with respect to the metal s free corrosion potential. Hydrogen was generated on the sample surface when the specimen was cathodic, and dissolution of the sample was encouraged when the sample was anodic. The results of these controlled potential tests showed no susceptibility of this alloy to SCC at anodic potentials. 

The most important application of chromium is in the production of steel. High-carbon and other grades of ferro-chomium alloys are added to steel to improve mechanical properties, increase hardening, and enhance corrosion resistance. Chromium also is added to cobalt and nickel-base alloys for the same purpose. 

The summary provided here illustrates the mechanical properties that characterize the transition metal carbides and nitrides. The materials are hard, strong, and somewhat brittle, and resemble ceramic substances. These properties are reviewed by Santhanam (chapter 2), who also describes the commonly used cobalt-binded cermets. 

T.D. Phillips, Effect of Gamma Radiation from Cobalt 60 on the Mechanical Properties of AHH and ARP Double-Base Solid Propellants , NPP TMR-159, Naval Powder Factory, Indian Head... 

Accurate control of microstructure on nanometric scale makes it possible to control magnetic and mechanical properties to a hitherto unattainable degree. In particular, magnetic nanostructures have recently become the subject of an increasing number of experimental and theoretical studies. The materials are made of alternating layers, around 10 A thick, of magnetic (e.g., cobalt) and nonmagnetic metals (e.g., copper). 

The two cobalt-molybdenum catalysts were characterized for their physical properties surface area (ASTM D-3663), pore volume, and average pore diameter (ASTM D-4222), mechanical properties crushing strength (ASTM D-4179), and attrition loss (ASTM D-4058), chemical composition, as well as carbon and sulfur content by coulometry. 

Lead Alloying lead with silver, tin, or cobalt often improves the corrosion resistance of lead anodes. In many cases, the surface of a lead anode is acmaUy lead dioxide [58]. Pb02 electrodes are stable in sulfate media at low pH and the oxygen overpotential is high, but the material has poor mechanical properties and corrodes in HCl. 

It is known that nature and quality of a catalyst carrier material is important to the performance of a catalyst. The carrier impacts the catalytic reaction and process by its chemical, physical or mechanical properties and/or provides co-catalytic function. An example for a typical support effect is the well-investigated standard reaction of ethane hydrogenolysis over nickel or cobalt on different support materials (Figure 1) [1] ... 

This section describes the production and characterisation of BN and B CyN nanostructures generated by arc discharge techniques and by pyrolysis of CHjCN-BClj over cobalt at 1000°C. The resulting graphite-like nanostructures show remarkable conducting and mechanical properties. 

The lattice of vanadium expands approximately linearly with the addition of aluminum [64]. The aluminum intermetallic compound, V3AI (V-25 atom% Al), expands the lattice by about 1% from 0.3025 nm in unalloyed vanadium to 0.3054 nm [64]. Molybdenum, cobalt and titanium also expand the lattice of vanadium, whereas elements such as chromium and iron cause the lattice to contract [83]. Addition of these elements can increase the mechanical strength of alloys relative to unalloyed vanadium [85]. For niobium and tantalum, mechanical properties can also be improved by alloying [86]. Buxbaum has patented a number of alloys of niobium, tantalum and vanadium for membrane use, including Ta-W, V-Co, V-Pd, V-Au, V-Cu, V-Al, Nb-Ag, Nb-Pt, Nb-Pd, V-Ni-Co, V-Ni-Pd, V-Nb-Pt, and V-Pd-Au [45]. 

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