The GATE Grind

GATE 2022 MT – Question 65

Metallurgical Thermodynamics · Phase equilibria and phase diagrams · 2 marks · Numerical answer

The equilibrium microstructure of an alloy A-B consists of two phases α and β in the molar proportion 2:1. If the overall composition of the alloy is 70 mol% B and the composition of β is 90 mol% B, the composition of α is ______ (in mol% B) (round off to the nearest integer).

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: 59 to 61

Explanation

Let alpha composition be $C_\alpha$ mol% B. The molar phase balance is $70=(2C_\alpha+90)/3$.

Thus $2C_\alpha=120$ and $C_\alpha=\boxed{60}$ mol% B.