Evaluation of Physicomechanical Properties of Ti-45Nb Specimens Obtained by Selective Laser Melting

Abstract

Porosity, values of nanohardness and Young’s modulus of the specimens obtained with the method of selective laser melting were measured with optical methods, scanning electron microscopy and Nano Hardness Tester NHT-S-AX-000X device for measuring physicomechanical properties. Ti-45wt%Nb powder obtained with mechanical alloying was used for selective laser melting. The results have shown that increased heat input due to the laser power growth up to 80 W and scanning speed decrease down to 40 mm/s decreases the porosity of the specimen. The nanohardness average value is not sensitive to the changes of scanning modes in the investigated range. The Young’s modulus decreases with energy input increase.

Advances in Laser Additive Manufacturing of Ti-Nb Alloys: From Nanostructured Powders to Bulk Objects

“…In addition, this could be due to the presence of a small amount of nanoscale α″-phase in the initial mechanically alloyed powder applied for LPBF. Such structure features and phase composition provide a reduced Young’s modulus of the alloy (in comparison with the modulus of pure components), which is in the range of 60–85 GPa for porous and dense samples, and increased microhardness of 7500 MPa [ 67 , 69 ].…”

“…The droplets that were created by the laser beam appear on the surface during the melting stage, to be later precipitated on the consolidated surfaces of molten pools. Then, the complete crystallization and formation of the rough surface with visible cavities appears, which is depicted in Figure 10 a [ 69 ]. In Figure 10 b, a more uniform and much smoother surface of a dense sample is represented.…”