Mechanical Properties of a Tetrahedrally Cored Titanium Lattice Structure Fabricated by Pressure-Assisted Investment Casting

Pressure-assisted investment casting based on the pressure differential between melting and casting chambers was used to fabricate a tetrahedral titanium lattice structure. The pressure differential between the melting chamber and the casting chamber effectively minimized the formation of the alpha-case layer and the tensile yield strength was barely influenced by the thin alpha-case layer. The effective compressive yield strength of the titanium lattice structure was dependent upon the number of cells. Cracks were generated at the joint of the struts in the titanium lattice structure during compression tests. An increased number of cells resulted in a decrease of the effective yield strength by concentrating stress at the joint between the struts where the bending stress was applied. As a result, the mechanical properties of the titanium lattice structure were strongly affected by structural morphology and the number of cells.