Effect of nano-TiB2 particles on the anisotropy in an AlSi10Mg alloy processed by selective laser melting

In components built by selective laser melting (SLM), possible anisotropy in microstructure significantly affects mechanical properties (i.e. service performance) and there is a constant effort to solve this problem. This work carried out a comparative study using fully dense AlSi10Mg alloy and in-situ nano-TiB2 decorated AlSi10Mg composite samples processed by SLM. The aim was at clarifying the effect of integrated nanoparticles on the anisotropy of the as-built component. Microstructure and texture evolution were investigated by scanning and transmission electron microscopy, electron backscatter diffraction, X-ray and neutron diffraction. The SLMed AlSi10Mg sample shows a coarse columnar grain structure with and fiber orientation texture and obvious anisotropy in mechanical properties. However, the nano-TiB2 modified AlSi10Mg sample exhibits fine equiaxed grains, no preferred crystallographic texture and remarkably reduced anisotropy. Besides, both tensile strength and ductility have been improved in the SLMed TiB2 decorated AlSi10Mg sample. The preliminary mechanism upon grain refinement effect due to nano-TiB2 particles on columnar-to-equiaxed transition and reduction of anisotropy was discussed. [Display omitted] •A competition growth of and fiber texture is found in SLMed Al alloy.•The introduction of TiB2 eliminates texture and anisotropic mechanical behavior.•Random orientation of TiB2 nucleation agents determines random orientation of Al.•Both strength and ductility have been improved in SLMed TiB2/AlSi10Mg alloy.