Additively manufactured novel Ti6Al7Nb circular honeycomb cellular solid for energy absorbing applications

This investigation addresses a novel additively manufactured circular honeycomb sample of the titanium alloy Ti6Al7Nb which exhibits superior mechanical properties compared to hexagonal honeycomb samples. Compared to other lattice structures/cellular solids of Ti-based alloys, the circular honeycomb sample provides an optimum combination of strength and fracture strain. During compression testing, the circular honeycomb exhibits a wide stress-strain curve with higher tensile stress and elongation compared to hexagonal honeycomb samples. The failure of the circular honeycomb sample occurs layer-by-layer, so the whole sample fails not before the fracture of all single layers of the cells in the circular honeycomb leading to higher elongations. In this regard, the hexagonal honeycomb sample fails by shear of struts oriented at 45 to the loading axis. The area near the fracture region shows a fine acicular alpha MODIFIER LETTER PRIME microstructure. Electron Backscattered Diffraction (EBSD) data analysis reveals coarse prior beta grains in the surrounding microstructure. So, the circular honeycomb sample is superior to the hexagonal honeycomb sample concerning impact and energy absorption applications.

Automated summary

This investigation examines a new additively manufactured circular honeycomb sample made of the titanium alloy Ti6Al7Nb. Compared to hexagonal honeycomb samples, the circular honeycomb shows superior mechanical properties. Compression testing reveals a wider stress-strain curve and higher tensile stress and elongation in the circular honeycomb sample. Failure occurs layer-by-layer in the circular honeycomb, while the hexagonal honeycomb fails due to shear of struts. The circular honeycomb sample is found to be superior in impact and energy absorption applications.