Effect of elemental interaction on microstructure and mechanical properties of FeCoNiCuAl alloys

FeCoNiCuAlX (X refers to Si, Cr, Ti, Zr and Nd) alloys were prepared using a suck-casting method. The effect of various elements on phase constituents, microstructures and mechanical properties of the alloys was investigated using X-ray diffraction (XRD), scanning electron microscopy, and compressive tests. It has been found that the microstructure and phase constituents remain unchanged when the Si, Cr and Ti are added into the FeCoNiCuAl alloy, which have a typical cast dendrite microstructure consisting of a dominated body-centered-cubic (BCC) solid solution and a face-centered-cubic (FCC) solid solution. However, the intermetallic compounds are formed in the alloys with the addition of Zr or Nd element. The compressive strength and plasticity of the alloys are enhanced by the addition of the Si, Cr and Ti, and retarded by the addition of the Zr or Nd element. The results have been discussed in aspects of atomic size difference, electronegativity difference, valance electron concentration and the mixing enthalpy among the elements in the alloys.