Elinvar alloys

The iron meteorites are mostly composed of the Fe-Ni alloy minerals kamacite, taenite, and tetrataenite, and are believed to be remnants of the cores of parent bodies. Grains of Fe-Ni alloys are also common in most other types of meteorites. Because of exceedingly low cooling rates from the melt (typically 1 K/Ma), the recovered materials are believed to be close to equilibrium structures and are therefore of interest to metallurgists, especially given the importance of industrial Fe-Ni alloys such as Invar (FeesNiss), Elinvar, and Permalloy. 

Elinvar /el-in-var/ (Trademark) An alloy of chromium, iron, and nickel. It is used for making hairsprings for clocks and watches because its elasticity does not vary with temperature. 

Mas] Masumoto, H., Sawaya, S., Kikuchi, M., Antiferromagnetic Elinvar-Type Alloys in the Mn-Cu-Fe System , Trans. Jpn. Inst. Met., 14, 171-176 (1973) (Experimental, Meehan. Prop., 4)... 

Asa decisive variable determining the properties of invar and elinvar alloys (Sect. 4.3.2.8). 

The term invar alloys is used for some groups of alloys characterized by having temperature-invariant properties, either temperature-independent volume (invar) or temperature-independent elastic properties (elinvar) in a limited temperature range. A comprehensive survey of the physics and applications of invar alloys is given in [3.17]. 

A schematic description of the components of the AE effect in ferromagnetic elinvar alloys is given in Fig. 4.3-46. 

The final processing steps consist of solution annealing at 1150 °C, water quenching, cold deformation, and a final precipitation annealing at about 600 °C. Accordingly commercial elinvar alloys are produced, such as those listed in Tables 4.3-28, 4.3-29, and 4.3-30. 

Apart from the well-tried Fe—Ni—Cr—(Be, Til-based elinvar-type alloys, Fe—Ni—Mo-based alloys have gained technical application. Addition of Mo improves the elastic properties, lowers the Curie temperature, and increases the resistance to corrosion. While in Europe and the USA, Fe—Ni-based elinvar-type alloys mainly were developed, in Japan Co—Fe-based elinvar alloys were discovered. Ternary Co—Fe—Cr alloys and quaternary alloys containing Ni (Co-elinvar) attained significant technical relevance. Distinguishing... 

Table ir.3-30 Co—Fe-based elinvar-type alloys (annealed state). Composition, thermal expansion coefficient a, Young s modulus E and shear modulus G, and their respective temperature coefficients, e and g [3.17]... 

Table i..3-30 Co—Fe-based elinvar-type alloys (annealed state). Composition, thermal expansion coeliicient a, cont. 

Table 4.3-32 Properties of an antiferromagnetic Fe—24Mn—8Cr—7Ni—0.8Be elinvar alloy [3.53] ...

Other Nonmagnetic Elinvar-Type Alloys. In general, the elastic constants decrease with increasing tern-... 

Elinvar behavior is, also, found in concentrated Nb—Zr and Nb—Ti alloys. Furthermore, some amorphous alloys, e.g., in the Fe—B-, Fe—P-, and Fe—Si—B-based systems, show elinvar behavior. Ex-arrqtles for amorphous Fe—B alloys are shown in Fig. 4.3-54. 

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