ductile or brittle

teng125

i force-elongation diagram, how can we know whether the material is ductile or brittle??any formula to calculate it??

pls help
thanx

Meson

They can be identify quite easily as the following:

If there is a very long section after yielding point, which we call the plastic deformation section, existing in the curve then it is ductile.

If the curve is basically just a short section of straigth line obeying Hooke's law followed by a small, short curve indicating the breaking point or UTS, then it is brittle.

PerennialII

Just keep in mind that the actual micromechanism of fracture is not always that straightforward to identify from a force-displacement curve, in a case where several coexist (for example brittle failure can result after quite extensive plasticity). Typical formula would be those typically related to stress-strain curves or then fracture mechanical ones (usually the former, but don't know the "level" of your problem).