Effect of Trace Scandium Addition on Al-6mg Alloy

Abstract

Ageing behaviour of Al-6Mg alloy doped with trace amount of scandium was investigated. Cold rolled and as cast samples were aged isochronally for 60 minutes at different temperature up to 500°C. Some samples were aged isothermally at 300°C for different periods ranging from 30 to 240 minutes. Hardness of the alloys was measured to study the age hardening effect due to scandium addition. Resistivity changes with annealing time and temperature were measured to understand the precipitation behaviour and recovery of strain of the alloy. Attempts were also made to understand quantitatively the grain refining effect of scandium in Al-6Mg alloy. Moreover, a kinetic analysis for precipitation in cold rolled experimental alloys has been carried out by Differential Scanning Calorimetric Technique to gain a clear understanding about the kinetics of recrystallisation and recovery in Al-Mg alloy with or without scandium additions. Keywords: Al-Mg alloys, Age hardening, Resistivity, Dendrites, Second phase. Journal of Mechanical Engineering Vol.36 Dec. 2006 pp.12-17DOI = 10.3329/jme.v36i0.806