Influence of Laser Strategies on Performance of Lattice Structures from Magnesium Alloy WE43 Produced by Laser Beam Powder Bed Fusion

Abstract

Lattice structures made of magnesium alloys are perspective for lightweight and biomedical applications. The processing of magnesium alloys and the production of complex geometries is possible with laser beam powder bed fusion. However, the small material volume of the lattice structures and the magnesium alloy require specific process parameters in order to achieve a high quality of the material. Therefore, the influence of two perspective laser strategies (contour strategy and hatch strategy), their combination, and skywriting is investigated. The geometry of the body-centered-cubic (BCC) lattice structure is used, representing the most difficult lattice structure to produce due to the struts inclination. A relative material density of over 99% is achieved with three laser strategies. The laser strategies have a direct influence on the pore distribution, pore shape, and microstructure. All these parameters can influence the mechanical performance of the BCC structures. The best performance is achieved with the hatch strategy with skywriting, which results in a low number of dangerous pores and a fine microstructure. The Young's modulus of material of 40 GPa and the effective elastic modulus of BCC structure of 136 MPa are achieved.Lattice structures made of magnesium alloys are perspective for lightweight and biomedical applications. The processing of magnesium alloys and the production of complex geometries is possible with laser beam powder bed fusion. However, the small material volume of the lattice structures and the magnesium alloy require specific process parameters in order to achieve a high quality of the material. Therefore, the influence of two perspective laser strategies (contour strategy and hatch strategy), their combination, and skywriting is investigated. The geometry of the body-centered-cubic (BCC) lattice structure is used, representing the most difficult lattice structure to produce due to the struts inclination. A relative material density of over 99% is achieved with three laser strategies. The laser strategies have a direct influence on the pore distribution, pore shape, and microstructure. All these parameters can influence the mechanical performance of the BCC structures. The best performance is achieved with the hatch strategy with skywriting, which results in a low number of dangerous pores and a fine microstructure. The Young's modulus of material of 40 GPa and the effective elastic modulus of BCC structure of 136 MPa are achieved.