(SEM III) THEORY EXAMINATION 2021-22 MATERIALS ENGINEERING

This is the B.Tech Semester III examination paper for Materials Engineering (KME303).
The exam carries 100 marks and comprehensively covers the structure, properties, phase transformations, heat treatment, failure theories, alloys, and mechanical behaviour of engineering materials.

The paper is designed to test a student’s conceptual understanding, analytical ability, diagram interpretation skills, and application of materials science concepts in real engineering problems.

The question paper is divided into three sections – A, B, and C.

SECTION A – Short Theoretical Questions (20 Marks)

This section contains 10 compulsory questions, each worth 2 marks.
They test fundamental knowledge of:

Unit cell in crystal structures

Ductility vs malleability

Stress intensity factor (fracture mechanics)

Drawing planes using Miller Indices (011), (001)

Gibbs phase rule

Use of phase diagrams

Critical cooling rate in heat treatment

Need for tempering after hardening

Brass vs bronze

Superalloys and examples

These questions check quick recall and basic concept clarity.

SECTION B – Descriptive / Analytical Questions (30 Marks)

Students must attempt any three out of five questions (each 10 marks). Topics include:

Classification of crystal defects with detailed explanation of point defects

Three theories of failure:

Maximum principal stress

Maximum shear stress

Maximum distortion energy

Alloy vs solid solution & Hume–Rothery rules of solid solubility

Heat treatment processes (annealing, normalizing, hardening) explained using Fe–C diagram

Cast iron types: grey, malleable, white, spheroidal — compositions & applications

This section evaluates the ability to explain concepts deeply, compare properties, and interpret diagrams.

SECTION C – Long Answer Numerical / Diagram-Based Questions (50 Marks)

There are five main questions (Q3 to Q7), each with two options. Students must answer one part from each question.

Q3 – Stress–Strain & Elastic Recovery

Stress–strain curve of steel + reason for two yield points + true stress vs engineering stress relation
OR

Numerical based on elastic and plastic deformation and recovery after unloading

Q4 – Fracture & Fatigue

Griffith theory for brittle fracture + critical crack size derivation
OR

Fatigue failure and development of S-N curve using RR Moore test

Q5 – Phase Diagrams

Iron–carbon diagram with all invariant reactions
OR

Lead–tin eutectic phase diagram + calculation of α and β phase fractions at eutectic point

Q6 – Surface Hardening / TTT Diagram

Surface hardening of steel with sketches (carburizing, nitriding, cyaniding etc.)
OR

Method for developing TTT curve + transformations (pearlite, bainite, martensite)

Q7 – Alloying & Special Alloys

Need for alloying steel + effects of elements (Cr, Ni, Mo, V, Mn, Si etc.)
OR

Composition & applications of common engineering alloys:

Monel metal

Muntz metal

Gun metal

Duralumin

Y-alloy

This section tests high-level understanding, phase transformation knowledge, diagrams, and real-world engineering material behaviour.

OVERALL SUMMARY

The Materials Engineering (KME303) question paper thoroughly evaluates:

Crystal structures & defects

Mechanical properties & failure theories

Phase diagrams (Fe-C, Pb-Sn)

Heat treatment processes

Stress–strain behaviour

Fracture & fatigue

Surface hardening

Alloy classification & compositions

Engineering alloys & applications

It combines short conceptual questions, descriptive theoretical explanations, diagram-based questions, and numerical problems, ensuring complete assessment of a student’s understanding of material science.