At low temperatures
some metals that would be ductile at room temperature become brittle. This is
known as a ductile to brittle transition.
The ductile to brittle
transition temperature is strongly dependant on the composition of the
metal.Steel is the most commonly used metal that shows this behaviour.
For some steels the
transition temperature can be around 0°C, and in winter the temperature in some
parts of the world can be below this. As a result, some steel structures are
very likely to fail in winter.
Example of Brittle Failure:
Ductile fracture is
always a preferred mechanism of failure. Many cases have occurred through
history where catastrophic failures have occurred as a result of brittle
fracture. The most infamous of these is the sinking of the Titanic.
The sinking of the titanic
was caused primarily by the brittleness of the steel used to construct the hull
of the ship. In the icy water of the Atlantic, the steel was below the ductile
to brittle transition temperature.
In these conditions
even a small impact could have caused a large amount of damage. The impact of
an iceberg on the ship's hull resulted in brittle fracture of the bolts that
were holding the steel plates together.
Nowadays engineers know
more about this phenomenon and the composition of the steels used is much more
controlled, resulting in a lower temperature at which the ductile to brittle
transition occurs.
