The effect of texture on the anisotropy of thermophysical properties of additively manufactured AlSi10Mg

The process of additive manufacturing (AM) has rapidly developed over the past two decades and is now addressing the needs of industry for fast production of samples with tailored properties and complex geometries. One of the most common alloys fabricated from powder using the Laser Powder Bed Fusion (L-PBF) method is AlSi10Mg. The effects of the inherent anisotropy and existing porosity in AM AlSi10Mg were investigated in terms of thermophysical properties, namely thermal conductivity, diffusivity, heat capacity and thermal expansion. These properties were measured in the two principal directions, namely parallel and perpendicular to the printing direction (i.e., in the Z- and X-directions, respectively). In both cases, the sample showed abnormal thermal expansion and conductivity, as compared to a conventionally fabricated sample. After heat treatment, macro- and microstructure analysis confirmed that thermally induced porosity (TIP) had occurred. The anisotropic behaviors of thermal conductivity, diffusivity and thermal expansion were found to be related to the texture, preferred orientation and pore distribution of the aluminum grains in the L-PBF-treated samples.