Lever rule: Difference between revisions
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==Calculations== |
==Calculations== |
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Before any calculations can be made a ''tie line'' is drawn on the phase diagram to determine the percent weight of each element; on the phase diagram to the right it is [[line segment]] LS. This tie line is drawn horizontally at the composition's temperature from the liquid to the solids. The percent weight of element B at the liquidus is given by ''w''<sub>l</sub> and the percent weight of element B at the |
Before any calculations can be made a ''tie line'' is drawn on the phase diagram to determine the percent weight of each element; on the phase diagram to the right it is [[line segment]] LS. This tie line is drawn horizontally at the composition's temperature from the liquid to the solids. The percent weight of element B at the liquidus is given by ''w''<sub>l</sub> and the percent weight of element B at the solidus is given by ''w''<sub>s</sub>. The percent weight of solid and liquid can then be calculated using the following lever rule equations:<ref name="smith"/> |
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idus is given by ''w''<sub>s</sub>. The percent weight of solid and liquid can then be calculated using the following lever rule equations:<ref name="smith"/> |
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:<math>\text{Percent weight of the solid phase} = X_s = \frac{w_o - w_l}{w_s - w_l}</math> |
:<math>\text{Percent weight of the solid phase} = X_s = \frac{w_o - w_l}{w_s - w_l}</math> |
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Revision as of 06:56, 26 May 2011
The lever rule is a tool used to determine weight percentages of each phase of a binary equilibrium phase diagram. It is used to determine the percent weight of liquid and solid phases for a given binary composition and temperature that is between the liquidus and solidus.[1]
Calculations
Before any calculations can be made a tie line is drawn on the phase diagram to determine the percent weight of each element; on the phase diagram to the right it is line segment LS. This tie line is drawn horizontally at the composition's temperature from the liquid to the solids. The percent weight of element B at the liquidus is given by wl and the percent weight of element B at the solidus is given by ws. The percent weight of solid and liquid can then be calculated using the following lever rule equations:[1]
where wo is the percent weight of element B for the given composition.
References
- ^ a b Smith, William F.; Hashemi, Javad (2006), Foundations of Materials Science and Engineering (4th ed.), McGraw-Hill, pp. 318–320, ISBN 0-07-295358-6.