|About this Abstract
||Materials Science & Technology 2019
||Advanced Manufacturing, Processing, Characterization and Modeling of Functional Materials
||Epitaxial Growth of a Magnetic Shape-memory Alloy: Laser Metal Deposition of Ni-Mn-Ga
||Jakub Toman, Peter Müllner, Markus Chmielus
|On-Site Speaker (Planned)
Functional magnetic shape-memory alloys (MSMAs) change shape when driven by a magnetic field – with strains of up to 12 % reported – and have enabled actuator, sensor and energy-harvester prototypes. While crystal growth is the incumbent method for production of MSMAs, its low throughput is a drawback. We investigate epitaxial growth by directed energy deposition as an alternative, which would allow imparting higher-order shape to MSMA elements. Our efforts in laser-based processing aim to produce columnar or single-crystalline material by epitaxial growth from single-crystal substrates. Examination of laser-melted tracks by EBSD showed overwhelming adoption of the crystal orientation of existing material, and formation of few stray grains. Expanding upon this, material was added by directed energy deposition, whereby powder is blown into the melt pool. Both types of tracks were later homogenized. Recrystallization occurred in some cases, confirming that heat treatment is a major challenge for this processing route.