The newest dissertation reveals the potential of additive manufacturing for facilitating the development of magnetic shape memory alloy actuators

MSc Ville Laitinen  will defend his dissertation in the field of Technical Physics at LUT University. His doctoral thesis is titled Laser powder bed fusion for the manufacture of Ni-Mn-Ga magnetic shape memory alloy actuators. It consists of a series of experimental investigations:  a laser powder bed fusion (L-PBF) additive manufacturing process and a subsequent heat-treatment process were developed for the manufacture of functional polycrystalline Ni-Mn-Ga-based magnetic shape memory (MSM) alloy.

The findings demonstrate that the chemical composition and resulting MSM-related properties of the L-PBF-built Ni-Mn-Ga can be precisely changed in-situ by adjusting the applied L-PBF process parameters to control the selective evaporation of Mn. A repeatable and fully reversible magnetic-field-induced strain of 5.8% is demonstrated for a single crystalline grain of an L-PBF-built Ni-Mn-Ga.

Practically, the reported results will permit the exploration of polycrystalline-MSM-based devices with a geometric freedom that has thus far been impossible with conventional manufacturing methods.