THERMOMECHANICAL TREATMENT OF 7003 ALUMINIUM ALLOY

Abstract

Thermomechanical treatment of 7003 aluminium alloy was studied by hardness measurement and tensile testing. 'The recommended ageing temperature of 155°C was employed along with 10 pet. and 20 pot- plastic deformation ' as an intermediate stage. Without thermomechaflical treatment It was found that peak hardness, corresponding ultimate tensile strength and elongation values are 109.0 V.P.N., ~1#«9 Kg/ 2 (2 X102 N/ni2) and 11.6 pct. respectively. With thermomechanical treatment consisting of certain amount of preageing before giving deformation and followed by further ageing, there was overall improvement in the mechanical properties and simultaneous reduction in the ageing time. The samples were given 2 pct. 1 50 pct. and 75 pct. preageing treatments before giving plastic deformation. The best combination of strength and elongation was obtained with 50 pct. of preageing at 15500 alongwith 20 pet. plastic deformation followed by further final ageing at 1550C. The values of peak hardness ! ultimate tensile strength and elongation in this case were 123.0 V.P.N., Kg/mm2 (337x102 N/m2) and 7.7 pet. respectively with total ageing time of 1+ hr +5 minutes.