Nickel tensile strength

Fig. 9. Effect of temperature on strength and ductiUty of a nickel-base superaHoy, IN-939, showing A, tensile strength B, 0.2% proof stress C, reduction in...

Tables 10 and 11 list typical compositions of cast and wrought cobalt-base alloys, respectively. Stress—mpture properties of two wrought cobalt alloys, Haynes 188 and L-605, are compared to those of iron—nickel alloys ia Figure 10 (49). The cobalt alloys generally are inferior ia strength to the strongest cast nickel-base superaHoys. Tensile strengths at low and iatermediate temperatures are particularly deficient for the cobalt alloys.

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. 

Tables 1 and 2, respectively, Hst the properties of manganese and its aHotropic forms. The a- and P-forms are brittle. The ductile y-form is unstable and quickly reverses to the a-form unless it is kept at low temperature. This form when quenched shows tensile strength 500 MPa (72,500 psi), yield strength 250 MPa (34,800 psi), elongation 40%, hardness 35 Rockwell C (see Hardness). The y-phase may be stabilized usiag small amounts of copper and nickel. Additional compilations of properties and phase diagrams are given ia References 1 and 2.

Properties of copper—nickel alloys are Hsted in Table 14. The alloys in the copper—nickel group have been successfully cast using the centrifugal, investment, permanent, and sand molding methods. The minimum tensile strengths on test bars cast in sand molds are 207—310 MPa (30,000—45,000 psi). 

Austenitic stainless steels are the most corrosion-resistant of the three groups. These steels contain 16 to 26 percent chromium and 6 to 22 percent nickel. Carbon is kept low (0.08 percent maximum) to minimize carbide precipitation. These alloys can be work-hardened, but heat treatment will not cause hardening. Tensile strength in the annealed condition is about 585 MPa (85,000 Ibf/in"), but workhardening can increase this to 2,000 MPa (300,000 Ibf/in"). Austenitic stainless steels are tough and ducdile. 

Nonmagnetic drill collars are manufactured from various alloys, although the most common are Monel K500 (approximately 68% nickel, 28% copper with some iron and manganese, and 316L austenitic stainless steel). A stainless steel with the composition of 0.06% carbon, 0.50% silicon, 17-19% manganese, less than 3.50% nickel, 12% chromium, and 1.15% molybdenum, with mechanical properties of 110 to 115 Ksi tensile strength is also used. 

Nickel normally crystallises in the f.c.c. structure it undergoes a magnetic transformation at 357°C and is ferromagnetic below that temperature. In all the alloys shown in Table 4.21 the f.c.c. (austenitic) structure is substantially retained, and in consequence most of the alloys possess the combination of properties required of materials for widespread industrial acceptability, i.e. tensile strength, ductility, impact strength, hardness, hot and cold workability, machinability and fabrication. 

Tench and White (12) have shown that the room-temperature tensile strength of CMA (composition-modulated alloy) Ni-Cu exhibits values around three times that of nickel itself. The hardness of the same CMA has been demonstrated by Gimunovich et al. (13) to be many times greater. This is so as long as the thickness of the CMA layers is less than lOOnm. Stress due to lattice mismatch may be the prime cause of this. 

P. It was developed by Chase Division, Kennecott Copper Corp., in 1950. The machinability rating is 80. The hot-working properties are comparable to those of a high copper commercial bronze and are superior to lead-containing free-machining copper alloys. The tensile strength is high, and the electrical and thermal conductivities are similar to those of nickel bronze CDA No. 191, and about one half those of copper (see Copper alloys). 

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