Ultimate Tensile Strength
Ultimate tensile strength (UTS) is the maximum stress that a material can withstand while being stretched before breaking. It is quite distincth from ultimate compressive strength – concrete can withstand much stronger forces in compression than tension.
The units of stress are the same as the units of pressure (or).
Some materials will fracture without warning or plastic deformation. These materials are brittle. Most metals, will experience some plastic deformation and possibly necking before fracture.
The highest point of the stress-strain curve is the UTS. UTS is a property of a material and does not depend on the size of the specimen (since it is defined as) but may be affected by the way the sample is prepared or the conditions eg temperature.