Compression and fatigue performance of Ti6Al4V materials with different uniform and gradient porous structures

Abstract

Ti6Al4V materials with porous structures exhibit good mechanical performance and biocompatibility, thereby enabling their prospective application in biomedical devices. In the study, porous samples were fabricated using intrinsic gas and condensation pores of the laser-powder bed fusion (LPBF) method. By changing the laser scanning speed from 150 mm/s to 430 mm/s, LPBF samples having porosity between 8.59% and 31.9% could be prepared. Compression tests were performed, which confirmed a decrease in the elastic modulus from 20.1 to 14.6 GPa. These samples satisfied the general bone requirement of 10–30 GPa. Moreover, bone-like gradient samples (with porosity radially increasing and decreasing) were printed and compressed. The samples also yielded to the rule that a higher porosity (average porosity) leads to a low elastic modulus. Further, a 30° fatigue test was conducted to measure the fatigue strength, a dynamic strength. The fatigue life was verified to be negatively related to porosity. However, even the longest fatigue life (less than 106 cycles) was lower than those of commercial bioimplants (several 107 cycles). Therefore, the fatigue life of the LPBF samples fabricated in this study require improvement.