First-principles study of mechanical properties of one-dimensional carbon nanotube intramolecular junctions

► Tensile-deformed CNT intramolecular junctions are investigated by first-principles. ► Bond breaking begins at a seven-membered ring at a junction. ► The position of pentagon-heptagon defects at a junction governs tensile stress-strain relationships. ► The applicability of the AIREBO to tensile-deformed CNT junctions is discussed. ► The AIREBO leads to an inappropriate representation of stress-strain relationship.