3D Printing of Active Metals

One of the research branches from additive manufacturing that has attracted interest in the last decade is printing of active materials (or 4D printing). Time is introduced as an additional parameter through materials that react to stimuli by changing their shape, properties or functionality.

Shape memory alloys (SMA) are metallic materials capable of recovering from strains past the elastic limit. Unlike conventional metals, they depend on solid-solid diffusionless phase transformations to return to the initial state. Consequently, they can also accommodate extraordinarily large deformations without showing brittle behavior. Analogous to thermally activated shape memory alloys, magnetic shape memory alloys (MSMAs) also show large recoverable deformation upon the application of a magnetic field.

The mechanical characterization of materials in various length scales is necessary after producing our samples. From macro-scale testing down to micromechanics, we work on studying the behavior and microstructure of the materials we work with. SEM micrographs overlaid with indentation mappings enable the clear visualization of mechanical properties over a surface area (a sintered 316L specimen in this case). This technique is crucial in multi-metal parts as different phases are revealed and can be correlated to data clusters in 2D histograms.