Al-bronze alloys are widely used to produce coin blanks owing to their superior corrosion and electrical conductivity properties. Coining is a closed die forging process, in which pressure is applied on the surface of the forging to obtain closer tolerances, smoother surfaces, and eliminate draft. This process mostly relies on refining microstructure but there can be severe effects on electrical conductivity after. In this study, variation of hardness and electrical conductivity properties of the aluminum bronze with cold rolling and recrystallization was investigated. Initially, the aluminum bronze alloy was hot-rolled from 165 mm to 25.46 and then CuAl6Ni2 was cold-rolled to 11.73 mm with a %55 reduction ratio and CuAl6Ni2 was cold-rolled to 6.27 mm with a %75 reduction ratio. Annealing of the cold-rolled samples was carried out at 450 ºC and 700 ºC for 7 hours each to observe the effect of annealing temperature. Samples were prepared to be analyzed under optical microscopy and microstructural analyses were conducted via optical microscope. Microhardness tests were performed and measured according to ASTM E384. The electrical conductivity of the samples was measured. Based upon the hardness and electrical conductivity tests results, a relationship between annealing temperature, hardness, and electrical conductivity for CuAl6Ni2 was examined.
Anahtar Kelimeler: CuAl6Ni2 alloy, Annealing, Recrystallization, Electrical conductivity
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