Manufacturing of Al-Al3Fe functionally graded material using the vacuum centrifugal method and measurements of its mechanical properties

Abstract

The centrifugal method is one of the functionally graded material (FGM) manufacturing methods proposed by the authors. However, there are certain difficulties in applying the centrifugal method to an alloy melt with high viscosity and low heat capacity. The centrifugal casting system under a vacuum condition is, thus, adopted and designed to improve the former system in air. A new system is satisfactorily constructed and Al-Al3Fe FGM of a thickwalled tube is manufactured from Al-10 mass.% Fe master alloy. The particles of intermetallics are confirmed to the Al3Fe intermetallic by EDX analysis. The graded composition of Al3Fe in aluminum matrix is examined and is varied from pure aluminum at inner surface of the tube to 40 vol% Al3Fe at outer plane of the tube. The corresponding graded Young's modulus and thermal expansion coefficient of Al-Al3Fe FGM vary from 71 to 99.5 GPa and from 25.5 ×p 10-6 to 21.3 × 10-5 K-1, respectively. Tensile tests are carried out using thin plate standard specimen for which Al3Fe grains are homogeneously distributed statistically. The averaged volume fraction of Al3Fe in the specimens, which are tested, is about 28 vol%. Tensile strength of 94 MPa at 0.49% tensile strain and Young's modulus of 90 GPa are obtained.