Karthik R
Strength can be various strengths such as Tensile, Compression or Flextural. In general strength means the maximum stress the material can withstand. In the above diagram point D represents the Ultimate Tensile Strength (UTS) of the material. Above this, the material starts to neck and then finally breaks.Toughness is the extend to which a material absorbs energy before it breaks during a tensile test. The area under the stress-strain curve is also an indication of the toughness of the material.Hardness is a surface property of the material . It represents the visco-elastic response of a material. In general a material is hard if it has a high tensile strength.