Tensile strength is an example of a mechanical evaluated material property. Tensile strength of a material is the amount of stress found at the point of failure when pulling apart.

Below a technician from Metaltest, Inc (a materials testing laboratory) is tensile testing a machined tensile sample

How can we change the Mechanical properties? 

We can change the mechanical properties of metals by alloying. The alloying of metals is one of the oldest and most fundamental material processing techniques. An Alloy is a solid solution that is composed of two or more elements. There is a solvent (majority composition) and a solute. The Solute element can strengthen the overall solid solution by different element size, density, and other material properties.

Steel is a wonderful example of alloying to increase tensile strength. Steel is an iron-base alloy, malleable in some temperature ranges as initially cast, containing manganese, usually carbon, and often other alloying elements. In carbon steel and low-alloy steel, the maximum carbon is about 2.0%; in high-alloy steel, about 2.5%. The dividing line between low-alloy and high-alloy steels is generally regarded as being at about 5% metallic alloying elements.