Types of Materials Failure

There are four types of material failure: deformation, fracture, corrosion, and wear.

Regarding Deformation:

Mechanical components change in shape and size under external force but do not crack or break off, and their functionality is affected, sometimes weakened or completely lost.

This is classified as stiffness failure or shape failure.

Regarding Fracture:

The component splits or breaks into two or more parts. This usually starts with tiny cracks that expand until the component is completely broken.

This is classified as strength failure, and the consequences are generally severe. The function is lost and it may also cause serious accidents.
 

Regarding Corrosion:

The component material undergoes chemical or electrochemical reactions with the surrounding medium (water, air, acids, alkalis, etc.) and gets 'eaten away.' Manifestations include rusting, peeling, pitting, thinning, perforation, and so on.

This type of material loss is classified as environmentally induced failure.
 

Regarding Wear:

Relative movement and friction between two contacting solid surfaces gradually wear away material, leading to material loss and eventual failure.

If wear is caused by a fluid (gas or liquid), it is generally called erosion.

Wear can cause the original component dimensions to shrink, surface roughness to increase, grooves to form, and gaps to widen, resulting in excessive clearance, increased vibration, noise, oil leakage, and loss of precision.