Home >>
ABSTRACT
Aluminium as a very common and important metal in engineering application owing to itsigh strength, low density, corrosion resistant and high electrical and thermal conductivity. It is normally not suitable for application in engineering activities until it is alloyed. Zinc (Zn) is one of the major alloying elements for aluminium alloys. This research investigated the effect of zinc contents on microstructure of aluminium-zinc alloy. Five different categories of the zinc alloys were developed with composition of zinc ranging from 2% to 10%. One of the specimens in each categories was Annealed, while the other was Age-hardened and the remainder left as cast. The specimens were polished, and then etched for observation under the Optical Metallurgical Microscope. The results shown that at low alloy contents, annealing favoured precipitation of spheroidized Zn, while age-hardening produced lenticular and botryoidal structures, which in moderate alloy content, annealing gave widmanstatten precipitate as against age-hardening spheroidized precipitate. The high alloy samples are both modified to dendritic structures and spheroidized precipitate for both annealing and age-hardening. Most of the Al-Zn alloys never contain up to 10%, but it is included in this research to reveal the possibility of obtaining Al-10%Zn alloy. The research significance is mostly in the area of materials science, which guide and direct materials scientists on the nature of microstructures.
Keywords: Aluminium, Zinc, Alloy, Annealing, Age-hardening, Etching, Microscope.
Full Text
