TITLE:
Effects of Variation of Some Process Variables on Recrystallization Rate of Aluminium Alloy (6063)
AUTHORS:
O.E. Olorunniwo, P.O. Atanda, K.J. Akinluwade
KEYWORDS:
recrystallization, holding time, plastic deformation, nucleation rate
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.8 No.1,
January
20,
2009
ABSTRACT: Effects of different annealing temperature, holding time and degree of deformation on
recrystallization rate of Aluminium alloy (6063) were studied. Fifteen suitably dimensioned
samples were prepared from Aluminium alloy (6063). Seven of these were subjected to 70% cold
plastic deformation, seven to 90% and one left undeformed. All the samples were then subjected
to annealing heat treatment to relief deformation-induced stresses. The average values of Yield
and Ultimate tensile loads were obtained from three preliminary tensile tests as 121.33 Kgf and
192.67 Kgf respectively. From these, 70 and 90% deformations were estimated. After a
metallographic test on the as-received, the samples were subjected to recrystallization annealing
under different conditions of temperature (380 ℃ and 450 ℃) and holding time (20, 30 and 40
minutes). Photomicrographs of the heat treated samples were taken from which the number of
grains was counted, with the aid of a magnifying lens, from a 1cm2 area inscribed on their
surfaces. The results obtained showed that the higher the degree of cold work, the higher the rate
of recrystallization, the higher the nucleation rate and the finer the grains. The higher the
holding time at a given recrystallization temperature, the larger the grains due to a longer time
available for grain growth. It was also deduced that recrystallization is thermally activated and
its rate increases with increase in temperature.