Material Science - short answer questions from AMIE exams

A brass plate contains a steel screw and it is being used in a marine environment. Which of the two metals would corrode faster and why?
The steel is on the higher side of the Galvanic series as compared to brass, so it will corrode faster.

What is the weight % of carbon in low carbon steel?
The percentage of carbon in low carbon steel is 0.05 to 0.3.

What is carburizing?
Carburizing is the diffusion or impregnation of carbon on the surface.

Whether duralumin is wrought or cast alloy?
It is a wrought alloy.

Name at least two mechanisms of plastic deformation.
Slip and Twinning. The key difference between slip and twinning is that during a slip, all atoms in a block move the same distance whereas, in twinning, the atoms in each successive plane in a block move through different distances that are proportional to their distance from the twinning plane.



Which of the two main mechanisms of plastic deformation requires greater shear stress to deform.
Slip

If you wound annealed MS and copper wire around your finger one of the two will not form a smooth circular. Which one?
Mild steel

Before cold working of AL alloy, it is heated to about 5840C and then quenched or it should be heated to a lower temperature of 100 to 2000C and then air-cooled?
They are heated to 5840C and quenched


For which type of fracture, the direction of crack propagation is very nearly perpendicular to the direction of applied tensile stress?
Brittle type of fracture. A brittle fracture is the fracture of a metallic object or other material without appreciable prior plastic deformation. It is a break in a brittle piece of metal that failed because stress exceeded cohesion. 



Brass and Bronze are alloys of copper. What are the other constituents in these alloys?
Brass has other constituents;  Zinc, Nickel and Lead Bronze has other constituents; Tin Phosphorous and Aluminium.

---
The study material for AMIE/B Tech/Junior Engineer exams is available at https://amiestudycircle.com

Comments

Post a Comment

Popular posts from this blog

Material Science Quiz (Mechanical Properties of Metals)

1. Time dependent permanent deformation is called ________________. (a) Plastic deformation (b) Elastic deformation (c) Creep (d) Anelastic deformation 2. Figure-out the odd point in the following (a) Proportinal limit (b) Elastic limit (c) Yeild point (d) Fracture point 3. If a material is subjected to two incremental true strains namely ε1 and ε2, then the total true strain is (a) ε1 * ε2 (b) ε1 - ε2 (c) ε1 + ε2 (d) ε1 / ε2 4. Engineering stress-strain curve and True stress-strain curve are equal up to (a) Proportional limit (b) Elastic limit (c) Yeild point (d) Tensile strength point 5. Value of Poisson’s ratio for ionic solids in the range of (a) 0.1 (b) 0.2 (c) 0.3 (d) 0.4 6. Hydrostatic stress results in the following (a) Linear strain (b) Shear strain (c) Both linear and shear strains (d) None 7. High elastic modulus in materials arises from (a) High strength of bonds (b) Weak bonds (c) combination of bonds (d) None 8. Change in elastic modulus for ordinar
Read more

Material Science (Corrosion & Degradation of Materials)

1.         Corrosion of metals involves (a) Physical reactions (b) Chemical reactions (c) Both (d) None 2.         The following factors play vital role in corrosion process (a) Temperature (b) Solute concentration (c) Both (d) None 3.         Following equation is related to corrosion rate (a) Nernst equation (b) Faraday’s equation (c) Either (d) Neither 4.         Passivity is due to (a) Higher EMF (b) Lower EMF (c) Oxide film (d) All 5.         Passivity is not reason for inertness of the following (a) Au (b) Al (c) Ti (d) Ni 6.         Difficult to monitor and very dangerous form of corrosion (a) Galvanic (b) Pitting (c) Crevice (d) Stress 7.         This form of corrosion occurs due to concentration difference in a component (a) Uniform (b) Galvanic (c) Inter-granular (d) Stress 8.         Main form of ceramic degradation (a) Corrosion (b) Weathering (c) Dissolution (d) Swelling 9.         The following influences deterioration of p
Read more

Material Science Quiz (Failure)

1. Failure due to excessive deformation is controlled by ______________. (a) Material properties (b) Design & Dimensions (c) Both (d) None 2. Failure due to excessive deformation is controlled by ______________. (a) Yield strength (b) Tensile strength (c) Young’s modulus (d) All 3. Time dependent yield is known as (a) Fracture (b) Fatigue (c) Buckling (d) Creep 4. Cleavage fracture appears (a) Bright (b) Dull (c) Difficult to identify (d) None 5. Usually materials with following crystal structure fail in ductile mode (a) FCC (b) BCC (c) HCP (d) None 6. Brittle fracture is more dangerous than ductile fracture because _______________. (a) No warning sign (b) Crack propagates at very high speeds (c) No need for extra stress during crack propagation (d) All 7. Fracture voids usually form at (a) Inclusions (b) Second phase particles (c) Grain boundary triple points (d) All 8. Fracture stress (σf) is proportional to (a) crack length (b) 1/crack length (c) (crac
Read more