Improvement of Tensile and Fracture Toughness Properties of Al 2014 Alloy Processed by Different Rolling Method followed by Post-ageing Treatment

Abstract

The present investigation focuses on the effect of artificial ageing treatment on solution treated AA 2014 alloy, cryo-rolled AA 2014 alloy deformed at true strain of 2.3 and cryo-groove-rolled AA 2014 alloy deformed at strain of 2.3. The microstructural features of deformed AA 2014 alloy were characterized by the scanning-electron microscopy and transmission-electron microscopy. The Vickers hardness testing, tensile testing and 3-point bend testing were performed on processed AA 2014 alloy to investigate the mechanical properties. The result indicates that the peak aged (artificial ageing at 160 °C for 16 h duration) cryo-groove rolled (CGR + PA) AA 2014 alloy sample has shown the enhanced mechanical properties (Hardness: 211 HV, YS: 445 MPa, UTS: 554 MPa, KQ: 45.11 MPa $$\sqrt m$$ , Kee: 45.44 MPa $$\sqrt m$$ and J integral: 50.86 kJ/mm2) in comparison to the rest of the processed sample conditions. The ductility of CGR + PA AA 2014 alloy got enhanced (i.e. 14.68%) with the post ageing treatment. The improvement in mechanical characteristics was attributed to precipitation hardening, strengthening of grain boundary, dynamic ageing and combined recovery and recrystallization effect during the process of deformation. It was observed that precipitation due to the metastable spherical phase Al2Cu was accountable for the enhanced fracture and tensile properties of CGR + PA AA 2014 alloy.