Properties of Metals
Most polycrystalline materials have within their elastic range an almost constant
relationship between stress and strain. Experiments by an English scientist named
Robert Hooke led to the formation of Hooke's Law, which states that in the elastic
range of a material strain is proportional to stress. The ratio of stress to strain,
or the gradient of the stress-strain graph, is called the Young's Modulus.
DEFINE the following terms:
Given stress-strain curves for ductile and brittle material,
IDENTIFY the following specific points on a stress-strain curve.
Given a stress-strain curve, IDENTIFY whether the type of
material is ductile or brittle.
Given a stress-strain curve, INTERPRET a stress-strain curve
for the following:
Application of Hooke's Law
The elastic moduli relevant to polycrystalline material are Young's Modulus of Elasticity, the
Shear Modulus of Elasticity, and the Bulk Modulus of Elasticity.
Young's Modulus of Elasticity is the elastic modulus for tensile and compressive stress and
is usually assessed by tensile tests. Young's Modulus of Elasticity is discussed in detail
in the preceding chapter.