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Asked: 2020-04-14T07:57:13+05:30 In:

BARC-1: In a Eutectic Phase Diagram, Lever Rule can be applied just above Eutectic Temp or Just below. But not at the Eutectic Temp. What is the Reason?

BARC-1: In a Eutectic Phase Diagram, Lever Rule can be applied just above Eutectic Temp or Just below. But not at the Eutectic Temp. What is the Reason?
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    1. Best Answer
      Platinum GATE Metallurgy Coaching | Faculty with 7 years of Teaching Experience | 50% of Selections in all PSUs
      This answer was edited.

      The answer is quite simple!! If you remember the derivation of Level Rule, it is derived for a Two-Phase Equilibrium. At the Eutectic Point, there is a three-phase Equilibrium and hence it cannot be applied !! :) :) We will post the Questions at the start of the Day and answers at the End of the DayRead more

      The answer is quite simple!!

      If you remember the derivation of Level Rule, it is derived for a Two-Phase Equilibrium. At the Eutectic Point, there is a three-phase Equilibrium and hence it cannot be applied !! 🙂 🙂

      We will post the Questions at the start of the Day and answers at the End of the Day !! Good Luck to all

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    2. Copper Undergrad. in Metallurgical and Materials Engineering from Malaviya National Institute of Technology, Jaipur
      This answer was edited.

      Because lever rule is used to find the composition of two phases that are in equilibrium. But at the eutectic point, the phases present are in dynamic equilibrium. To apply a mass balance equation there were require one more parameter i.e rate of heat. Without knowing how much heat is taken out or hRead more

      Because lever rule is used to find the composition of two phases that are in equilibrium. But at the eutectic point, the phases present are in dynamic equilibrium. To apply a mass balance equation there were require one more parameter i.e rate of heat. Without knowing how much heat is taken out or how much heat is given to the system we can’t apply any mass balance equation. So we’re not able to apply lever rule at the eutectic point.

      Whereas we can apply above and below eutectic temperature because equilibrium present there is not dynamic.

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    3. Lever rule can be applied on two phase region

      Lever rule can be applied on two phase region

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    4. Gold Metallurgist, Standard Provider (IS, ASTM, BS, ISO etc), Laboratory Equipment Suppliers,
      This answer was edited.

      The lever rule is a rule used to determine the mole fraction or the mass fraction  of each phase of a binary equilibrium phase diagram. It can be used to determine the fraction of liquid and solid phases for a given binary composition and temperature that is between the liquidus and solidus line. ThRead more

      • The lever rule is a rule used to determine the mole fraction or the mass fraction  of each phase of a binary equilibrium phase diagram.
      • It can be used to determine the fraction of liquid and solid phases for a given binary composition and temperature that is between the liquidus and solidus line.

      • There is now more than one two-phase region. The tie line drawn is from the solid alpha to the liquid and by dropping a vertical line down at these points the mass fraction of each phase is directly read off the graph, that is the mass fraction in the x axis element. The same equations can be used to find the mass fraction of alloy in each of the phases, i.e. wl is the mass fraction of the whole sample in the liquid phase
      • Conclusion : Lever Rule can’t applied on Eutectic Point due to three phase, it describes two phase equilibrium. 
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    5. Because , the eutectic point is an invariant point in which the possibility of distinguishing a variable or degrees of freedom is zero

      Because , the eutectic point is an invariant point in which the possibility of distinguishing a variable or degrees of freedom is zero

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    6. Silver Metallurgical Engineering student

      Lever rule is used to find out the weight percentages in an alloy at particular composition of an alloy.

      Lever rule is used to find out the weight percentages in an alloy at particular composition of an alloy.

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    7. Copper

      In the thermodynamic view. The interaction parameter (omega) come into  picture.. 1. At the eutectic line(below or above) the interaction parameter close to zero but not zero. So the phases are miscible.(nither repulsive nor attractive to each other) So this is what causes dynamic equilibrium.. As wRead more

      In the thermodynamic view.

      The interaction parameter (omega) come into  picture..

      1. At the eutectic line(below or above) the interaction parameter close to zero but not zero.

      So the phases are miscible.(nither repulsive nor attractive to each other)

      So this is what causes dynamic equilibrium..

      As we going far from line this interaction parameter changes..  So we can not calculate.

       

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    8. Platinum Metallurgical and Materials Engineering student

      Because eutectic point is an invariant point where degree of freedom is zero so lever rule is applied above or below eutectic point.

      Because eutectic point is an invariant point where degree of freedom is zero so lever rule is applied above or below eutectic point.

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    9. Silver

      At eutectic point all three phases coexist with each other.

      At eutectic point all three phases coexist with each other.

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