Main material mechanical properties are:

Hardness is the resistance of a material to plastic indentation. Hardness values are roughly proportional to the strength of a metal and can give an indication of the wear properties of a material. Hardness values can be useful during the materials selection process and for quality-control evaluations, but the values cannot be applied directly during the design of a part.

Ductility is the capability of a material to deform plastically without fracturing, and it is usually measured by the amount that a bar under tensile load will elongate before fracturing. The elongation is expressed as a percentage of the original length of the bar.

Strength is the ability of a material to withstand an applied force, and three types are commonly discussed. Elastic strength, referred to as the elastic limit, is strength before the material deforms permanently. The yield strength is the strength of a material before appreciable plastic deformation occurs. The ultimate tensile strength is the maximum strength that a metal exhibits during tensile deformation.

Toughness is the ability of a metal to absorb energy in the plastic range. Although there are a number of approaches for defining toughness, one of the oldest is to consider it as the total area under the stress-strain curve. This area is an indication of the amount of work per unit area that can be done without causing it to fail. Because toughness is the area under the stress-strain curve, it is a function of both strength and ductility.