Effects of Variation of Some Process Variables on Recrystallization Rate of Aluminium Alloy (6063)

O.E. Olorunniwo, P.O. Atanda, K.J. Akinluwade

Department of Materials Science and Engineering Obafemi Awolowo University, Ile-Ife. Nigeria..

DOI: 10.4236/jmmce.2009.81001                

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.

Keywords

recrystallization, holding time, plastic deformation, nucleation rate

Conflicts of Interest

The authors declare no conflicts of interest.

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