What is “tensile strength”, “yield points” and “elongation”?
Greenwood: You may want to clarify your statement that “metals typically break without significant strain.” For an easy example, consider a paper clip. You can load it elastically (so that it recovers its original shape,) or bend it well past its elastic yield point into significant plastic deformation before rupture or fracture occurs. The plastic yield strain of most metals is many times the elastic strain limit. But on to the original question: On a load / deformation plot (or stress / strain plot), the tensile strength is the force (or stress) at which the specimen breaks. This is usually called the “ultimate” tensile strength. The yield point is the last strain (and corresponding stress) where unloading would be accompanied with a return of the specimen to its original shape. In other words, if it were loaded any further, it would have yielded and undergone permanent deformation (also called plastic deformation.) Elongation (or strain) is just the change in length of the tensile s
