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Handbook Properties and Selection Nonferrous Alloys and Spl Purpose Mtls (1992) WW Part 14

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Tham khảo tài liệu 'handbook properties and selection nonferrous alloys and spl purpose mtls (1992) ww part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Resistance to specific according agents. Lutetium does not react with cold or hot water but it reacts vigorously with dilute acids. Concentrated sulfuric acid slowly attacks lutetium. The presence of the fluoride ion retards acid attack due to the formation of LuF3 on the surface of the metal. Mechanical Properties Tensile properties. About the same as those of erbium Hardness. 44 HV Poisson s ratio. 0.261 Elastic modulus. At 27 C tension 68.6 GPa shear 27.2 GPa bulk 47.6 GPa Elastic constants along crystal axes. At 27 C c11 86.23 GPa c12 32.0 GPa c13 28.0 GPa c33 80.86 GPa C44 26.79 GPa Liquid surface tension. 0.940 N m at 1665 C Mischmetal MM Compiled by K.A. Gschneidner Jr. and B.J. Beaudry Ames Laboratory U.S. Department of Energy Iowa State University Mischmetal is used as an alloying additive in ferrous alloys to scavenge sulfur oxygen and other substances. Mischmetal is also added to magnesium-base alloys to improve high-temperature strength and to ductile irons to nodularize graphite. It is used as a reductant to produce the volatile rare earth metals samarium europium and ytterbium from their oxides. Other uses of mischmetal include lighter flints galvanizing alloys and mischmetal cobalt cerium-free mischmetal-nickel alloys are used as hydrogen storage alloys and permanent magnets. Mischmetal oxidizes at room temperature in air. Turnings can be ignited easily and burn white hot. Finely divided mischmetal should not be handled in air. Because mischmetal is an indefinite mixture of rare earth metals the properties of a particular mischmetal depend on its composition which in turn depends on the mineral source for the mixture. Listed below are the properties of two of the most common high-purity mischmetal mixtures. Because most commercial mischmetals contain several atomic percent of iron and magnesium about 1 wt their properties may differ somewhat from those listed below. Many values are estimated and are marked as such. Bastnasite-Derived Mischmetal .