Material Science - Jun 2015
Mechanical Engg (Semester 3)
TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.
Answer any one question from Q1 and Q2
1 (a) What do you mean by the term 'Unit Cell' ? Define various lattice parameters.(4 marks) 1 (b) Differentiate between cold working and hot working according to temperature, variation in mechanical properties, grain formation and areas of application.(4 marks) 1 (c) What is composite material ? Explain with classification and types.(4 marks) 2 (a) What do you mean by the term ?Polymer? ? Explain with types, characteristics and applications.(4 marks) 2 (b) What do you mean by the term 'ceramic' ? Explain with types, properties and application.(4 marks) 2 (c) Derive the expression for deformation of single crystal by slip? State the condition for geometrical hardening and geometrical softening.(4 marks)
Answer any one question from Q3 and Q4
3 (a) What is the concept of True stress and True strain ? Derive
the relations between them also find out the condition for
3 (b) What do you mean by the term 'Hardness of the material' ?
Explain any four testing methods for checking the hardness
of the material.(4 marks)
3 (c) What do you mean by 'non-destructive testing' ? Explain ultrasonic method of testing with working principle, advantages and drawbacks.(4 marks)
4 (a) Identify the methods of NDT in the following cases:
(i) Cavities, cracks or region of variable density for the metal/ non-metallic components manufactured by casting, welding and forging etc.
(ii) To sort out dissimilar metals and detect differences in their composition, microstructure etc.
(iii) Detecting internal defects such as cracks, porosity and laminations in metallic and non-metallic components during or after production.
(iv) Various kinds of flows in ferromagnetic components made from various welding, castings and forging etc.
(v) Invisible cracks, porosity and other similar defects on the surface of components made up of metal, non-metal, plastic, glass etc.(5 marks) 4 (b) Explain with working principle the material test for the component which shows a plastic deformation under constant stresses for a longer time at high temperatures. Draw the type of possible microstructure during this test.(4 marks) 4 (c) What is the purpose of 'Impact Test' ? Explain with types and the factors affecting the impact values of the component.(4 marks)
Answer any one question from Q5 and Q6
5 (a) Define the term 'powder metallurgy' with steps of processing and classification of powder manufacturing processes.(5 marks) 5 (b) What do you mean by the term 'sintering'? Explain the stages of sintering.(4 marks) 5 (c) Explain the role of powder metallurgy for manufacturing of 'cemented carbide'?(4 marks) 6 (a) Explain powder metallurgy with characteristics of metal powders, advantages, disadvantages and areas of applications.(5 marks) 6 (b) What do you mean by conditioning of metal powders? Explain with purpose and different processing stages.(4 marks) 6 (c) What is a 'self-lubricated bearing' ? Explain the role of powder metallurgy for manufacturing of 'self-lubricated bearings'.(4 marks)
Answer any one question from Q7 and Q8
7 (a) Explain the following terms (any two):
(i) Piezometric materials
(ii) Soft and hard ferrites
(iii) Super-conductors.(4 marks) 7 (b) What do you mean by the term 'biomaterials' ? Explain with different types?(4 marks) 7 (c) Explain the concept of 'shape memory alloy' with advantages, disadvantages and applications.(4 marks) 8 (a) Explain the following terms (any two):
(i) Cryogenic applications of smart materials
(ii) Modern materials for high temperature applications
(iii) Dielectric materials.(4 marks) 8 (c) Explain 'Biosensors' with principle, advantages and applications.(4 marks)