1st Paragraph: The effects of Fe and Ni additions on the electrical conductivity, thermal conductivity, microhardness and microstructure of pure Al was investigated. Both Fe and Ni have low solubility in solid Al and therefore form hard intermetallic phases, which are beneficial for producing strong, conductive alloys for electrical and thermal design requirements. Pure Al was melted at 730 °C, and 0.6, 1, 1.5 and 3 wt.% Fe or Ni was added and stirred into the melt before pouring into a steel mold. With increasing Fe content, the castings showed increases in microhardness and contained Al-Fe intermetallic phases with blocky as well as needle morphologies. With the addition of Ni, the formation of Al3Ni intermetallic phases increased alloy hardness. On a per weight percent basis, Fe additions were found to add 3.9 HV/wt.% to microhardness and reduce electrical conductivity by 3.4 % IACS/wt.%. For Ni addition, the increase in microhardness and decrease in electrical conductivity were 4.3 HV/wt.% and 1.7 % IACS/wt.%, respectively. Both Fe and Ni additions show potential for the production of cast Al alloys that are both strong and conductive.
Authors: S. Kotiadis, A. Elsayed, E. Vandersluis, and C. Ravindran
Keywords: thermal conductivity, electrical conductivity, aluminum alloys, microhardness, microstructure