Formation of Microstructure and Mechanical Characteristics in Electron Beam Additive Manufacturing of Aluminum Bronze with an In-Situ Adjustment of the Heat Input

Microstructure and mechanical characteristics of aluminum bronze fabricated using electron beam additive manufacturing (EBAM) under adjusting the heat input as a function of the sample’s height are investigated. It is shown that this adjustment has an effect on the dendrite grain size, morphology and mechanical characteristics. Columnar high aspect ratio grains are formed during deposition at the maximum heat input values. The columnar grain width in the section parallel to the deposition direction is increasing in the EBAM conducted at a lower heat input. The tensile static tests show that the tensile strength values are improving from 435 to 483 MPa. A moderate degree of anisotropy is revealed between the samples oriented by their tensile axes parallel and perpendicular to the deposition direction. The samples with tensile axes parallel to the deposition direction show higher tensile strength and lower plasticity than those of the samples with perpendicular orientations of their tensile axes. Furthermore, the heat input adjustment has no effect on the mean width of the columnar grains measured in a section perpendicular to the deposition direction.