Question

1(a)
Draw a schematic representing a dislocation, in 2D.
(b)
Describe what is meant by work-hardening? Explain with an example.
(c)
Assume you are stretching a bar of metal that undergoes work hardening. What would the Stress vs Strain diagram of such a material look like, showing deformation behaviour?
(d)
Define the Following:
(i) What is a Fracture?
(ii) Define the types of Fracture.
(iii) Draw the types of Fractures.
(iv) What is Fracture Toughness?
(v) What are Stress Concentrators?

(e)

State at least two situations in which the possibility of failure is part of the design of the component or Product.

Answer 1

Ans A)

Ans B)

work hardening is commonly known as stress hardening. It is the process use to strengthening the metal by performing the plastic deformation. The strengthening happen because of the dislocation movements and dislocation generation within the crystal structure of the material. example - bending the thin steel rod becomes more difficult the farther the rod is bent.

Ans C)

AnsD)

(i) fracture is basiaclly known as the point where the test material (specimen) break into two pieces that is it also known as breaking strength. It is the stress at which a specimen fails via fracture.

(ii) the type of fracture is depend upon the shape of the end of breaking specimen, whether is is round, point etc.

(iv) in simple word, we can say that it is the resistance (property) of the material which describe the ability of the material to resist fructure without fail.

(V) It is point inside the material where we can assume that whole stress is concentrated. An object is seem to be stronger when the applied force is evenly distributed over its area, so there is a reduction in area, example caused by a crack, results in a localized increase in stress.