2030 – 02 – The Origin of Mechanical Properties

1m

A metal’s mechanical properties are related to how its atoms are arranged. This arrangement, or crystal structure, is an unchanging pattern. This structure is the most efficient way for the atoms to arrange themselves.
Metals are typically one of three types of crystal structures.
– HCP structures tend to be very brittle because of the way that they are packed together. HCP metals include titanium and magnesium.
– FCC metals usually are ductile because their atoms slide around easier than HCP structures. FCC metals include aluminum, nickel, lead and gold.
– Metals with a BCC structure tend to be hard, but not as ductile. Iron, tungsten and chromium are BCC metals at room temperature.
Any metal that is subject to stress for a long enough time will begin to fail. The crystal structure determines how quickly the breakdown happens.