Chapter 7.10, Problem 1KCP

What are the characteristics of the surface of a ductile fracture of a metal?

To determine

The characteristic of a surface of a ductile fracture of a metal.

Explanation of Solution

When a material undergoes plastic deformation, ductile fracture occurs. The characteristics of a surface of a ductile fracture of a metal are listed below:

$1.$ The stress exceeds the value of ultimate tensile strength and the crack generates slowly.

$2.$ The crack starts moving toward the surface of the material.

$3.$ The crack is about to touch the surface, the direction changes to $45°$ to the tensile axis and as a result the cup and cone fracture appears.

The below figure represents the ductile fracture of a specimen and the plot between stresss and strain of ductile material.

Figure-(1)

The point $\text{Y}$ on the graph is the yield point where yielding phenomenon occurs. The point $\text{U}$ is the point of ultimate tensile stress. At this point the material is under maximum stress condition. The point $\text{F}$ is the point of fracture at which the material breaks.