What are the key points on a stress-strain curve from a tensile test?

Key points include: Proportional limit (Hooke's Law valid), Elastic limit (end of elastic behavior), Yield point (onset of plastic deformation), Ultimate Tensile Strength (maximum stress), and Fracture point (failure). The area under the curve up to UTS represents toughness, while the slope in the elastic region gives Young's Modulus.