  Two unique behaviors of superelasticity and shape memory effect have made
shape memory alloy such as NiTi, an interesting alloy for different
applications. Recently, additive manufacturing (AM) as a powerful tool for
fabricating NiTi has become of interest to make complex geometries. Selective
laser melting (SLM) is an AM method that not only provides flexibility to make
complex 3D shapes but also it can be possible to tailor the thermomechanical
properties of the parts just by changing the process parameters. The
non-homogeneous microstructure of as-fabricated parts as well as asymmetric
mechanical behavior of NiTi, make it important to study the properties of SLM
NiTi parts under different loading condition. In this study, Ni50.8Ti (at. %)
powder was utilized to fabricate cube, dog-bone, and tube by SLM technique. The
transformation temperatures (TTs) of samples were measured by the differential
scanning calorimetry (DSC) method and the variation of TTs was discussed. Three
coupons were tested mechanically under compression, tension, and torsion.
In-situ digital image correlation (DIC) was employed to measure and monitor the
strain field of samples during the mechanical tests. The strain distribution
showed localized strain for all three samples. The equivalent stress/strain was
calculated to compare the result of compressive, tensile, and torsional
responses and the significant asymmetric behavior was shown and discussed.
