Researchers construct thermodynamic databases for multicomponent alloys. (General Developments).Thermodynamic ther·mo·dy·nam·ic adj. 1. Characteristic of or resulting from the conversion of heat into other forms of energy. 2. Of or relating to thermodynamics. modeling allows the prediction of the phases present in complex alloys composed of many elements. Such phase equilibria calculations can be used to show composition, crystal structure, and volume fraction of the various phases, and can be determined from the extrapolation (mathematics, algorithm) extrapolation - A mathematical procedure which estimates values of a function for certain desired inputs given values for known inputs. If the desired input is outside the range of the known values this is called extrapolation, if it is inside then of thermodynamic descriptions of the constituent binary and If two conditions are combined by and, they must both be true for the compound condition to be true as well. Likewise, two bits may be combined with and: x y x AND y 0 0 0 0 1 0 1 0 0 1 1 1 I.e. ternary (programming) ternary - A description of an operator taking three arguments. The only common example is C's ?: operator which is used in the form "CONDITION ? EXP1 : EXP2" and returns EXP1 if CONDITION is true else EXP2. systems. Properties of a system, such as phase boundaries and enthalpies are described with one set of functions resulting in a consistent description of phase properties. The approach gives reasonable predictions for complex alloys and provides a compact storage method for massive amounts of phase diagram phase diagram, graph that shows the relation between the solid, liquid, and gaseous states of a substance (see states of matter) as a function of the temperature and pressure. data. Researchers at NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. have constructed a thermodynamic database for Ni-base alloys. The NIST Ni-superalloy thermodynamic database includes 10 elements, Ni-Al-Co-Cr-Hf-Mo-Re-Ta-Ti-W and describes properties of the liquid and the two most important solid phases, [gamma] and [gamma]' Data were derived from both critically evaluated literature and NIST work. As a result of this work, detailed solidification behavior for Ni-base superalloys can be predicted. This capability is now being used by the casting industry to shorten the development process. The same methodology was used by the researchers to develop a thermodynamic database for solder alloys. This database includes seven elements, Sn-Ag-Bi-Cu-In-Pb-Sn, and has been used to evaluate freezing ranges for new environmentally friendly Environmentally friendly, also referred to as nature friendly, is a term used to refer to goods and services considered to inflict minimal harm on the environment.[1] , lead-free solders, as well as the effects of potential Pb contamination of these solders. Electronic versions of the NIST thermodynamic databases have been distributed to various industries, universities, and national laboratories and are available from the Web site http://www.metallurgy.nist.gov/phase/. This Web site also features a series of calculated binary and ternary phase diagrams for solder alloys as well as examples of the application of phase equilibria information to practical problems. CONTACT: Ursula Kattner, (301) 975-6044; ursula.kattner@nist.gov. |
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