Laser Beam Powder Bed Fusion of Co–Ni–Ga Shape Memory Alloy Using Single-Crystalline Substrate Material

Abstract In the present study, a Heusler-type Co–Ni–Ga shape memory alloy (SMA) was additively manufactured using laser beam powder bed fusion (PBF-LB/M). This alloy system is known for its promising superelastic properties in single-crystalline state. Polycrystals, however, suffer from premature failure due to intergranular cracking under thermo-mechanical loading and/or processing. In order to overcome this issue, an appropriate microstructure design is of utmost importance for envisaged applications. The present study reports on the use of single-crystalline substrate plates as seed crystals during PBF-LB/M processing. Detailed microstructure analysis reveals the influence of processing parameters and scanning strategies on the solidification behavior and microstructure evolution with increasing built height. Eventually, a promising PBF-LB/M processing routine for obtaining additively manufactured Co–Ni–Ga structures with good shape memory effect is established.