GATE ME concept:phase-diagrams PYQs & Answers

Questions 1–5 of 5. Imported answers require independent review unless marked reviewed.

A steel sample with 1.5 wt.% carbon (no other alloy elements present) is slowly cooled from 1100 °C to just below the eutectoid temperature (723 °C). A part of the iron-cementite phase diagram is shown in the figure. The ratio of the pro-eutectoid cementite content to the total cementite content in the microstructure that develops just below the eutectoid temperature is ________. (Rounded off to two decimal places)

Diagram for Mechanical Engineering question 52

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In Fe-Fe₃C phase diagram, the eutectoid composition is 0.8 weight % of carbon at 725 °C. The maximum solubility of carbon in α-ferrite phase is 0.025 weight % of carbon. A steel sample, having no other alloying element except 0.5 weight % of carbon, is slowly cooled from 1000 °C to room temperature. The fraction of pro-eutectoid α-ferrite in the above steel sample at room temperature is

Your answerChoose one option.

0.387

0.864

0.475

0.775

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Which one of the following statements about a phase diagram is INCORRECT?

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It indicates the temperature at which different phases start to melt

Relative amount of different phases can be found under given equilibrium conditions

It gives information on transformation rates

Solid solubility limits are depicted by it

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The binary phase diagram of metals P and Q is shown in the figure.

Diagram for Mechanical Engineering question 34

An alloy X containing 60% P and 40% Q (by weight) is cooled from liquid to solid state. The fractions of solid and liquid (in weight percent) at 1250 °C, respectively, will be

Your answerChoose one option.

77.8% and 22.2%

22.2% and 77.8%

68.0% and 32.0%

32.0% and 68.0%

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Denoting L as liquid and M as solid in a phase-diagram with the subscripts representing different phases, a eutectoid reaction is described by

Your answerChoose one option.

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GATE ME concept:phase-diagrams PYQs

How to practice concept:phase-diagrams

Question 52

Question 41

Question 11

Question 34

Question 12