Alloys chemical composition

Corrosion Resistance Possibly of greater importance than physical and mechanical properties is the ability of an alloys chemical composition to resist the corrosive action of various hot environments. The forms of high-temperature corrosion which have received the greatest attention are oxidation and scaling. 

Table 4,26 Some common wrought copper-aluminum alloys chemical composition...

Table 4.30 Some common cast copper-tin alloys, chemical composition ...

Alloy Chemical composition, % by weight Mechanical properties ... 

Many primary and secondary lead producers offer a range of products in addition to refined metal, but the degree of product differentiation and value-added is generally limited. These may include various lead alloys, chemicals, composite materials and semi-fabricated (rolled, cast or extruded) goods. Although some refiners may also be involved in the manufacture of intermediate or end-use lead products (like cable sheathing, proprietary chemicals. 

Many alloying elements in Ni-base superalloys are only of small quantities despite their critical contributions to the superalloy s properties and applications. The carbon content is usually from 0.02 to 0.2 wt%, boron from 0.005 to 0.03 wt%, and zirconium from 0.005 to 0.1 wt%. To reproduce these alloys without knowing their original design details, reverse engineering needs to accurately analyze the alloy chemical composition, particularly the quantitative analysis of the critical elements that appear only in trace amounts. 

To define a steel, it would be necessary to know its chemical composition, its physicochemical constitution, its metallurgical state (aimealed, hammered) and other parameters (superficial and chemical processing,. ..). The set of structural characters of a metallic alloy is consequently function of the chemical composition, the elaboration processing, the thermal processing, the temperature, etc. 

The tables in this section contain values of the enthalpy and Gibbs energy of formation, entropy, and heat capacity at 298.15 K (25°C). No values are given in these tables for metal alloys or other solid solutions, for fused salts, or for substances of undefined chemical composition. 

AWS) has issued specifications covering the various filler-metal systems and processes (2), eg, AWS A5.28 which appHes to low alloy steel filler metals for gas-shielded arc welding. A typical specification covers classification of relevant filler metals, chemical composition, mechanical properties, testing procedures, and matters related to manufacture, eg, packaging, identification, and dimensional tolerances. New specifications are issued occasionally, in addition to ca 30 estabUshed specifications. Filler-metal specifications are also issued by the ASME and the Department of Defense (DOD). These specifications are usually similar to the AWS specification, but should be specifically consulted where they apply. 

Table 4. Chemical Compositions and Physical Properties of Magnesium Cast and Wrought Alloys ...

Table 5. Nominal Chemical Composition of Nickel Alloys, wt %...

The uses of steel are too diverse to be Hsted completely or to serve as a basis of classification. Inasmuch as grades of steel are produced by more than one process, classification by method of manufacture is not advantageous. The most useful classification is by chemical composition into the large groups of carbon steels, alloy steels, and stainless steels. Within these groups are many subdivisions based on chemical composition, physical or mechanical properties, or uses. 

The physical and mechanical properties of steel depend on its microstmcture, that is, the nature, distribution, and amounts of its metaHographic constituents as distinct from its chemical composition. The amount and distribution of iron and iron carbide determine most of the properties, although most plain carbon steels also contain manganese, siUcon, phosphoms, sulfur, oxygen, and traces of nitrogen, hydrogen, and other chemical elements such as aluminum and copper. These elements may modify, to a certain extent, the main effects of iron and iron carbide, but the influence of iron carbide always predominates. This is tme even of medium alloy steels, which may contain considerable amounts of nickel, chromium, and molybdenum. 

The nominal chemical composition and identification of the most important copper castiag alloys are Hsted ia Table 7. These alloys are ideatifted by name and by the Unified Numbering System. The use of names is not recommended. 

Samples were tested on in a melt of salts (75% Na SO, 25% NaCl) at 950°C in an air atmosphere for 24 hours. Micro X-rays spectrum by the analysis found that the chemical composition of carbides of an alloy of the ZMI-3C and test alloys differs noticeably. In the monocarbide of phase composition of an alloy of the ZMI-3C there increased concentration of titanium and tungsten is observed in comparison with test alloys containing chemical composition tantalum. The concentration of more than 2% of tantalum in test alloys has allowed mostly to deduce tungsten from a mono carbide phase (MC) into solid solution. Thus resistance of test alloys LCD has been increased essentially, as carbide phase is mostly sensitive aggressive environments influence. The critical value of total molybdenum and tungsten concentration in MC should not exceed 15%. 

For water, organic and water-organic metal salts mixtures the dependence of integral and spectral intensities of coherent and non-coherent scattered radiation on the atomic number (Z), density, oscillator layer thickness, chemical composition, and the conditions of the registering of analytical signals (voltage and tube current, tube anode material, crystal-analyzer) was investigated. The dependence obtained was compared to that for the solid probes (metals, alloys, pressed powder probes). 

As we have already seen, when an alloy contains more of the alloying element than the host metal can dissolve, it will split up into two phases. The two phases are "stuck" together by interphase boundaries which, again, have special properties of their own. We look first at two phases which have different chemical compositions but the same crystal structure (Fig. 2.5a). Provided they are oriented in the right way, the crystals can be made to match up at the boundary. Then, although there is a sharp change in... 

---