Formation of microstructures and mechanical characteristics in electron beam additive manufacturing of an aluminum bronze with in-situ adjusting 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 have been investigated. It was shown that such an adjustment of the heat input had effect on the dendrite grain size and morphology as well as mechanical characteristics. Columnar high aspect ratio grains were formed during deposition at maximum heat input values. The columnar grain width in section parallel to the deposition direction was increasing in EBAM conducted at lower heat input. Tensile static testing showed that the tensile strength values were improving from 435 to 483 MPa in the process. Some moderate degree of anisotropy has been revealed between samples oriented by their tensile axes parallel and perpendicular to the deposition direction. Samples with tensile axes parallel to the deposition direction showed higher tensile strength and less plasticity as compared to those of samples with perpendicular orientations of their tensile axes. In addition, the heat input adjustment had no effect on the mean width of columnar grains measured in a section perpendicular to the deposition direction.