Title£º Microstructure characterization and hardness of Al-Cu-Mn eutectic alloy
Author£º Yusuf Kaygisiz
Address£º Department of Electricity and Energy, Technical Vocational School of Sciences, Aksaray University, Aksaray, Turkey
Key words£º directional solidifi cation; aluminum alloys; microstructure; hardness test
CLC Nmuber£º TG146.21
Document Code£º A
Article ID£º 1672-6421(2018)05-390-07

The composition of Al-Cu-Mn ternary eutectic alloy was chosen to be Al-32.5wt.%Cu-0.6wt.%Mn to the Al2Cu and Al12CuMn2 solid phases within an aluminum matrix (¦Á-Al) from its melt. The Al-32.5wt.%Cu-0.6wt.%Mn alloy was directionally solidifi ed at a constant temperature gradient (G=8.1 K.m-1) with different growth rates, 8.4 to 166.2 ¦Ìm.s-1,by using a Bridgman-type furnace. The eutectic temperature (the melting point) of 547.85 ¡ãC for the Al-32.5wt.%Cu-0.6wt.%Mn alloy was obtained from the DTA curve of the temperature difference between the test sample and the inert reference sample versus temperature or time. The lamellar spacings (¦Ë) were measured from transverse sections of the samples. The dependencies of lamellar spacings (¦ËAl-Al2Cu) and microhardness on growth rates were obtained as, ¦ËAl-Al2Cu=3.02V -0.36, HV=153.2(V)0.035 , HV=170.6(¦Ë)-0.09 and HV=144.3+0.82(¦ËAl-Al2Cu)-0.50, HV=149.9+53.48V0.25 , respectively, for the Al-Cu-Mn eutectic alloy. The bulk growth rates were determined as ¦Ë2 Al-Al2Cu.V = 25.38 ¦Ìm3.s-1 by using the measured values of ¦ËAl-Al2Cu and V. A comparison of present results was also made with the previous similar experimental results.