I'm going absolutely nuts over this chapter....ther seem to be millions of terms,which all seem to mean the same thing...could someone help me out?? Okay,the first set of questions I would like to get cleared is.... 1. The proportional limit on a stress-strain curve is supposed to be the point upto which the strain obeys Hooke's law and perfect elasticity is exhibited...but then what is the elastic limit for? 2.I read that 'The nonlinearity in the stress-strain curve between the proportional limit and the elastic limit refers to strain hardening and plastic flow is induced here'...but I thought that plastic flow occurs only after the yield point.....please explain. 3.what happens beyond the yield point,when the wire elongates,even without the application of stress?(in terms of dislocations,slip,etc.) 4. In the purely plastic region of the curve,why does the curve first rise,and then go down again (till fracture)? 5.How do we differentiate creep,dislocation climb and strain hardening?