Skip to main content

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

Popular posts from this blog

Energy Systems (Solved Numerical Problems)

Wind at 1 standard atmospheric pressure and \({15^0}C\) has velocity of 15 m/s, calculate (i) the total power density in the wind stream (ii) the maximum obtainable power density (iii) a reasonably obtainable power density (iv) total power (v) torque and axial thrust Given: turbine diameter = 120 m, and turbine operating speed = 40 rpm at maximum efficiency. Propeller type wind turbine is considered. (AMIE Winter 2023) Solution For air, the value of gas constant is R = 0.287 kJ/kg.K 1 atm = 1.01325 x 105 Pa Air density \(\rho  = \frac{P}{{RT}} = \frac{{1.01325x{{10}^5}}}{{287}}(288) = 1.226\,kg/{m^3}\) Total Power \({P_{total}} = \rho A{V_1}^3/2\) Power density \(\begin{array}{l}\frac{{{P_{total}}}}{A} = \frac{1}{2}\rho {V_1}^3\\ = \frac{1}{2}(1.226){(15)^3}\\ = 2068.87{\mkern 1mu} W/{m^2}\end{array}\) Maximum power density \(\begin{array}{l}\frac{{{P_{\max }}}}{A} = \frac{8}{{27}}\rho A{V^3}_1\\ = \frac{8}{{27}}(1.226){(15)^3}\\ = 1226{\mkern 1mu} W/{m^2}\end{array}\) Assuming eff...

Mechanics of Fluids (Solved Numerical Problems)

Numerical The surface Tension of water in contact with air at 20°C is 0.0725 N/m. The pressure inside a droplet of water is to be 0.02 N/cm² greater than the outside pressure. Calculate the diameter of the droplet of water. (7 marks) (AMIE Summer 2023) Solution Surface tension, σ = 0.0725 N/m Pressure intensity, P = 0.02 N/m 2 P = 4σ/d Hence, the Diameter of the dropd = 4 x 0.0725/200 = 1.45 mm Numerical Find the surface tension in a soap bubble of 40 mm diameter when the inside pressure is 2.5 N/m² above atmospheric pressure. (7 marks) (AMIE Summer 2023) Answer: 0.0125 N/m Numerical The pressure outside the droplet of water of diameter 0.04 mm is 10.32 N/cm² (atmospheric pressure). Calculate the pressure within the droplet if surface tension is given as 0.0725 N/m of water. (AMIE Summer 2023, 7 marks) Answer: 0.725 N/cm 2   Numerical An open lank contains water up to a depth of 2 m and above it an oil of specific gravity 0.9 for a depth of 1 m. Find the pressure intensity (i) at t...

Geotechnical & Foundation Engineering (Solved Numerical Problems)

Numerical A 1000 cc core cutter weighing 946.80 g was used to find out the in-situ unit weight of an embankment. The weight of the core cutter filled with soil was noted to be 2770.60 g. Laboratory tests on the sample indicated a water content of 10.45 % and specific gravity of solids of 2.65. Determine the bulk unit weight, dry unit weight, void ratio, and degree of saturation of the sample. (AMIE Summer 2023, 8 marks) Solution Weight of soil in core cutter = 2770.60 - 946.80 = 1823.8 g Bulk unit weight, γ t = W/V = 1823.8/1000 = 1.82 g/ccDry unit weight, γ d = γ t /(1 + w) = 1.82/(1 + 0.1045) = 1.65 g/cc Void ratio, e = (G s γ w /γ d ) - 1 = (2.65 x 1.0/1.65) - 1 = 0.61 Degree of saturation, S = wG s /e = (0.1045 x 2.65)/0.61 = 0.4540 = 45.4% Numerical What is the theoretical height of the capillary rise and the capillary pressure in fine-grained soil with an effective size (D 10 ) of 0.002 mm? (AMIE Summer 2023, 4 marks) Solution D 10 = 0.002 mm;  Using the assumption that th...