Investigating the Effect of Inclination Angle and the Influence of Scan Parameters on the Appearance and Thermal and Mechanical Properties of Filigree Tension Rods of LPBF‐Manufactured NiTi Shape‐Memory Alloys

NiTi powder is processed into tensile rods with a diameter of 150–220 µm using laser powder bed fusion with identical laser and scan parameters to investigate their properties as a function of the inclination angle to the build platform. Metallographic analysis shows that the melt pools in inclined rods (inclination angles >0° and <90°) extend partially perpendicularly into the powder bed due to the delicate nature of the structures and poor heat dissipation of the powder bed compared to the solidified material. Chemical analysis confirms the results of the thermal characterization: the nickel content decreases with increasing inclination angle, causing the transformation temperatures to rise. This behavior is reflected in the mechanical behavior, which, with identical manufacturing parameters, ranges from elastic–plastic behavior to martensite detwinning under load. In a second step, the scan parameters are adjusted as a function of the inclination angle with the intention to minimize the differences in properties. However, the results show that no significant changes in the thermal and mechanical properties are achieved, and therefore the scan vector length plays a minor role in the properties of such filigree structures compared to other parameters.