Material Science Engineering Answers

A diffusion couple is made from nickel and iron. After 30 hours of heat treatment at 1400 K, the concentration of nickel is 3.2 wt % at a distance of 1.5 mm from interface. If an identical diffusion couple is heated at 1200 K for 30 hours, at what depth from the interface will the concentration of nickel be 3.2 wt %? The pre-exponential factor (Do) and activation energy for diffusion is 1.8 x 10-5 m2 /s and 152 kJ/mol respectively, and the surface concentration of nickel is 100 wt%. (Note that this is a non-steady state diffusion process

Look at your surroundings and select a material on your choise and write a note about it

A diffusion couple is made from nickel and iron. After 30 hours of heat treatment at 1400 K, 

the concentration of nickel is 3.2 wt % at a distance of 1.5 mm from interface. If an identical 

diffusion couple is heated at 1200 K for 30 hours, at what depth from the interface will the 

concentration of nickel be 3.2 wt %? The pre-exponential factor (Do) and activation energy for 

diffusion is 1.8 x 10-5 m2

/s and 152 kJ/mol respectively, and the surface concentration of nickel

is 100 wt%. (Note that this is a non-steady state diffusion process).

It is found that the energy required to reduce particles from a mean 

diameter of 2 cm to 0.5 cm is 9 kJ kg

-1

. Estimate the energy 

requirement to reduce the same particles from a diameter of 0.4 cm 

to 0.03 cm assuming:

(a) Kick's Law,

(b) Rittinger's Law,

(c) Bond's Equation.

. A length of lead piping is 50.0 m long at a temperature of 16°C. When hot water flows through it the temperature of the pipe rises to 80°C. Determine the length of the hot pipe if the coefficient of linear expansion of lead is 29 × 10 -6 K -

Sketch and describe vaccum bag moulding process

how to find the allowable strength of a material?

A balloon has a volume of 4.0 L when at sea level (1.0 atm) at room temperature 0f 28 . C What will be its volume when inflated with inflated with the same amount of gas at an elevation where the atmospheric pressure is 700 mm Hg at 28 . C

Aluminium is used in food containers for different reasons: it provides a very good barrier to

protect food against light and air and preserves food quality; it is corrosion resistance; it can be

recycled and designed individually according to customers’ requirements; it can be produced

in different sizes and shapes due to its atomic bonding and its FCC crystalline structure.

However, in order to produce aluminium cans, manufacturers must strip-mine bauxite ore to

gain alumina. This method leaves behind liquid waste that can pollute soil and groundwater.

1. Suggest one other type of other crystalline solid (it can be polymer, ceramics, or other

metal), can replace aluminium as food packaging but with less impact on our soil and

groundwater. Justify your answer (cost of the material is not a factor)

2.suggestion,explain the mechanical properties of the material and relate

these properties to the atomic bonding and the crystalline structure of the material.

Compare these properties to aluminium.

A well-designed drill bit minimizes the risk of burning your fingers when you remove the bit from the drill. To achieve that goal, an important design objective is to minimize the heat flow along its length while simultaneously making sure the drill bit doesn’t mechanically fail during operation. Assume the maximum temperature generated at the drill bit tip is attained quickly and remains constant so that the temperature gradient, Δ𝑇, along the shaft is constant with time. The length, L, of the shaft is fixed but its radius, R, is variable.

a.Derive the material index for this application. Assume the heat, q, flow is:

𝑞=(𝜆Δ𝑇𝜋𝑅^2)/𝐿 where 𝜆 is the thermal conductivity,and the failure torque is:𝑇f=(𝜋𝑅^3𝜎y)/4 Start the problem by listing the objective, constraints and free variables