(SEM VIII) THEORY EXAMINATION 2016-17 ADVANCE MATERIAL TECHNOLOGY

SECTION A (Brief Answers)

Plain Carbon Steel vs Tool Steel
Plain carbon steel mainly contains iron and carbon with small amounts of other elements and is used for general applications. Tool steel contains higher carbon and alloying elements like tungsten, chromium, or vanadium, providing high hardness and wear resistance.

Normalizing of Steel
Normalizing is a heat treatment process in which steel is heated above its critical temperature and then cooled in air. It refines grain structure and improves strength and toughness.

Applications of Plain Carbon Steel
Plain carbon steel is used in construction materials, machine parts, automotive components, and structural applications.

Advantages of High Temperature Resistance Steel
These steels maintain strength and resist oxidation at elevated temperatures. They are used in boilers, turbines, and heat exchangers.

Radioactive Waste Disposal
Radioactive waste is disposed of by methods such as deep geological burial, vitrification, and secure containment to prevent environmental contamination.

Biomaterials
Biomaterials are materials used to replace or repair biological tissues. They must be biocompatible and non-toxic.

Process Annealing
Process annealing is a heat treatment used to relieve internal stresses and improve ductility in cold-worked steel.

Properties of Aluminum Alloy
Aluminum alloys are lightweight, corrosion resistant, and have good thermal and electrical conductivity.

Applications of Smart Materials
Smart materials are used in sensors, actuators, aerospace components, and medical devices because they respond to external stimuli.

Classification of Aluminum Alloys
Aluminum alloys are classified as wrought and cast alloys. Wrought alloys are further divided into series like 1xxx to 7xxx based on alloying elements.

SECTION B (Medium Length Answers)

T-Series and M-Series High Speed Steel
T-series high-speed steels contain tungsten, chromium, vanadium, and carbon. M-series steels contain molybdenum instead of tungsten. Ceramic coatings like TiN or Al₂O₃ improve wear resistance, reduce friction, and increase tool life.

Normalizing of 0.3% Carbon Steel
Steel with 0.3% carbon is heated above critical temperature and air cooled. This produces fine pearlite structure, improving strength and toughness compared to untreated steel.

Dispersion Strengthened Composites
These materials contain fine particles dispersed in a metal matrix, improving strength at high temperatures. Their mechanical properties are superior because dispersed particles hinder dislocation movement.

Mechanical Properties of Biomaterials
Biomaterials require high strength, fatigue resistance, corrosion resistance, and biocompatibility. Testing includes tensile tests, hardness tests, fatigue tests, and corrosion tests.

Breeder Reactors and Heavy Water
Breeder reactors produce more fissile material than they consume. Heavy water acts as a moderator in nuclear reactors because it slows down neutrons effectively without absorbing them significantly.

Stainless Steels
Stainless steels contain chromium for corrosion resistance. Types include austenitic, ferritic, and martensitic stainless steels. Austenitic stainless steel contains high chromium and nickel, offering good corrosion resistance and ductility.

Induction Hardening vs Flame Hardening
Induction hardening uses electromagnetic induction for surface heating and is faster and more controlled than flame hardening. Surface hardening improves wear resistance.

Refractory Coatings on Alloys
Methods include plasma spraying, thermal spraying, and chemical vapor deposition. These coatings improve high-temperature resistance and oxidation resistance.

SECTION C (15-Mark Style Answers)

Nuclear Materials
Nuclear materials include fissile, fertile, and moderator materials. Fissile materials like Uranium-235 can sustain chain reaction, while fertile materials like Uranium-238 can be converted into fissile material. Control rods and moderators are also important components.

Biomaterials (Steels, Polymers, Ceramics, Composites)
Steels such as stainless steel are used in surgical tools and implants. Polymers like polyethylene are used in joint replacements. Ceramics such as alumina are used in dental implants. Composites combine materials to improve strength and compatibility.

Refractory Coatings on Alloys
Refractory coatings are applied using thermal spraying or vapor deposition. They enhance oxidation resistance and thermal stability. Applications include turbine blades and furnace components.