Tensile Behavior of Additively Manufactured NiTi

Tensile test specimens were fabricated from a Ni₅₀Ti₅₀ (at.%) alloy powder utilizing the AconityMINI® PBF-LB system. The processing conditions were set to 180 W laser power, 1200 mm/s scan speed, 70 µm hatch spacing, spot size was 50 µm, layer thickness was 40 µm, and the scan pattern was bi-directional as per simulation pattern No3 (0°, 90°), shown in Fig. 2c. Testing was carried out according to ASTM E8/E8M standard, using four (4) small size round specimens of length, 29 mm; diameter 4 mm and gauge length 10 mm. Tensile testing was performed to failure using a 50 kN Zwick/Roell testing system with a crosshead speed of 1 mm/min and a preload of 5 N in the specimen build direction. A Class B-1 axial extensometer (Epsilon Technology Corp) was utilized to record specimen elongation during testing. The resultant material properties used for the simulation are presented in Table 2.Table 2

Average tensile test results for Ni₅₀Ti₅₀ martensitic printed via PBF-LB, n = 5

Property	Value
Yield strength	188.87 MPa
Elastic modulus	34.03 GPa
Poisson ratio	0.33