# Shared Flashcard Set

## Details

Material Science
Chapter 9
12
Mechanical Engineering
10/29/2012

## Additional Mechanical Engineering Flashcards

Term
 Component
Definition
 Components are pure metals and/or compounds of which an alloy is composed.
Term
 System
Definition
 May refer to a specific body of material under consideration. Or it may relate to the series of possible alloys consisting of the same components, but without regard to alloy composition.
Term
 Solubility Limit
Definition
 For many alloy systems and at some specific temperature, there is a maximum concentration of solute atoms that may dissolve in the solvent to form a solid solution.
Term
 Phase
Definition
 A phase may be defined as a homogenous portion of a system that has uniform physical and chemical characteristics.
Term
 Equilibrium
Definition
 The state of a system in which the phase characteristics remain constant over indefinite time periods. At equilibrium the free energy is a minimum.
Term
 Free Energy
Definition
 A function of the internal energy of a system and also the randomness or disorder of the atoms or molecules ( or entropy).
Term
 Phase equilibrium
Definition
 Equilibrium as it applies to systems in which more than one phase may exist. This is reflected by a constancy with time in the phase characteristics of a system.
Term
 Metastable
Definition
 The state of equilbrium is never completely achieved because the rate of approach to equilibrium is extremely slow; such a system is said to be in a nonequilibrium.
Term
 Phase diagram
Definition
 A graphical representation of the relationships among environmental constraints, composition, and regions of phase stability, ordinarily under conditions of equilibrium.
Term
 Isomorphous
Definition
 Having the same structure. In the phase diagram sense, isomophicity means having the same crystal structure or complete solid solubility for all compositions.
Term
 Tie Line
Definition
 For an alloy having composition and temperature located in a two-phase region, the situation is more complicated. One may imagine a series of horizontal lines, one at every temperature or sometimes as an isotherm.
Term
 Level rule
Definition
 A mathematical expression, such as Equation 9.1b or Equation 9.2b, whereby the relative phase amounts in a two-[phase alloy at equilibrium may be computed.
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