Elastic plastic energy very small toughness unreinforced polymers engineering tensile strain ε engineering tensile stress σ small toughness ceramics large toughness metals adapted from fig.
Stress strain curve of metals ceramics and polymers.
Elastic energy ductile fracture.
Difference between metals ceramics and polymers with respect to modulus and tensile strengths the modulus values for highly elastic polymeric materials are lower than those of metals.
Based on the mentioned properties.
A highly elastic polymer may stretch over 10 times the original length before breaking while a metal might elastically stretch 10 of the original length elastically and may stretch plastically to double the original length before reaching its fracture point.
While some of the stress strain curves for polymers might look similar to ones for metals polymers are mechanically different than metals or ceramics.
Low carbon steel generally exhibits a very linear stress strain relationship up to a well defined yield point fig 1.
A typical stress strain curve would look like figure 6 2strain curve.
Primarily differences are due to their different chemical bonding properties homework 1.
The stress strain curve for metals ceramics and polymers the curve i have shown you is a typical curve for ductile materials.
The linear portion of the curve is the elastic region and the slope is the modulus of elasticity or young s modulus.
For brittle ceramics a three point bending apparatus shown in the figure below is used determine the stress strain behavior and the measurement results are used to calculate an equivalent modulus of elasticity.
Stress strain curves for two brittle materials.
Plasticity happens when the atoms slip when they break bonds and reform new ones.
It makes them dense and eventuall.
Metals and its alloys contain atoms that are arranged in orderly manner.
Elasticity ductility and tensile strength those four materials can be simplified by these definitions.
Many ductile materials including some metals polymers and ceramics exhibit a yield point.
Stress strain curves for metals ceramics and polymers objective we are interested about studying and comparing stress strain curves of metals ceramics and polymers.
This stress curve is typical for ductile metallic elements.
Approximate by the area under the stress strain curve brittle fracture.
Stress strain curve is the plot of stress and strain of a material or metal on the graph.
In this the stress is plotted on the y axis and its corresponding strain on the x axis.
Metallic bonding is great for this sort of re bonding which is why metals are usually ductile.
In reality not all stress strain curves perfectly resemble the one shown in strain figure 6 2.
