This set of Materials Science Mcqs focuses on “Binary Phase Diagrams”.
1. How many components are present in binary phase system?
Explanation: In binary phase system there will be only two components.
2. The line above which the alloy is liquid is called __________
a) Solidus line
b) Tie line
c) Liquidus line
d) Lever line
Explanation: The liquidus line is the line above which the alloy is liquid. At the temperature just below this line crystal of solid solution start forming.
3. It can be noted that the two substances are soluble in each other in the entire range of compositions in both liquid and solid state. This kind of system is known as ___________
a) Binary phase system
b) Unary phase system
c) Multiple phase system
d) Isomorphous system
Explanation: Here, the two metals are soluble in all states.
Explanation: To find the composition of the individual phases in the two phase region, a line (XY) which is horizontal, called tie line, is drawn and its intercepts on the liquidus and solidus lines.
5. What is α region?
a) Homogeneous liquid solution
b) Semi solid solution
d) Substitutional solid solution
Explanation: The solidus line is a line below which solidification completes. Hence, the only αsolid solution exists at any temperature below the solidus line.
6. What is used for determination of Phase amounts?
a) Tie line and Temperature–Composition Point
b) Lever line
c) Temperature–Composition Point
Explanation: The above mentioned methods help in finding percentage fractions of phases.
7. A 53% Ni Cu-Ni alloy is cooled from the liquid state to 1300°C. Calculate the % of liquid and solid at 1300°C.
a) 28, 72
b) 38, 62
c) 35, 65
d) 65, 35
Explanation: The tie line at 1300ﹾC intersects solidus at 58% Ni and liquidus at 45% Ni.
Apply the lever rule to get the liquid fraction
% Liquid = 100* (5)/(13) = 38%
%Solid = 100* (53 – 45)/(58 – 45) = 62% (100 – %Liquid).
8. From the figure, the relative fractions of the phases at a given temperature for an alloy composition Co is obtained by the __________
a) Lever rule
b) Tie line
c) Solidus line
d) Liquidus line
Explanation: For two phase system lever rule helps i.e. the tie line must be utilized in conjunction with a procedure that is often called the lever rule.
9. What is the equation for liquid mass fraction?
a) cα – c0 / cα – cL
b) c0 – cL / cα – cL
c) cα / cα – cL
d) c0 / cα – cL
Explanation: Cα is composition of solid, CL is composition of liquid, C0 is composition of alloy.
10. What is the region between liquidus and solidus lines?
a) Two-phase region where liquid and solid coexist
b) Solid region
c) Liquid region
d) Lava region
Explanation: The intermediate region between liquidus and solidus lines is the two-phase region where liquid and solid coexists.
Sanfoundry Global Education & Learning Series – Materials Science.
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