Stress–strain curve of a metalधातु का प्रतिबल-विकृति वक्र

NCERT Fig 8.3 · interactive diagram

Parts and their functions

• O to A: Hooke’s law region (O से A: हुक के नियम का क्षेत्र) — Stress ∝ strain; the slope is Young’s modulus.
• A to B: still elastic, not linear (A से B: प्रत्यास्थ पर रैखिक नहीं) — Removing the load still returns the body to its original size.
• A: proportional limit (A: आनुपातिक सीमा) — Last point where stress ∝ strain.
• B: yield point (elastic limit) (B: पराभव बिंदु (प्रत्यास्थ सीमा)) — Stress here is the yield strength σ_y. Beyond it the deformation is permanent.
• Plastic region (सुघट्य क्षेत्र) — Large strain for little extra stress; unloading follows a line parallel to OA.
• Permanent set (स्थायी विरूपण) — Strain left when the load is removed after crossing B.
• D: ultimate tensile strength (D: चरम तनन सामर्थ्य) — Maximum stress the material can bear; beyond D it necks.
• E: fracture point (E: भंजन बिंदु) — D and E close ⇒ brittle; far apart ⇒ ductile.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 8.3. Report a mistake