RESUMO
Erosion and erosion-corrosion tests of as-built Ti-6Al-4V manufactured by Selective Laser Melting were investigated using slurries composed of SiO2 sand particles and either tap water (pure water) or 3.5% NaCl solution (artificial seawater). The microhardness value of selective laser melting (SLM)ed Ti-6Al-4V alloy increased as the impact angle increased. The synergistic effect of corrosion and erosion in seawater is always higher than erosion in pure water at all impact angles. The seawater environment caused the dissolution of vanadium oxide V2O5 on the surface of SLMed Ti-6Al-4V alloy due to the presence of Cl- ions in the seawater. These findings show lower microhardness values and high mass losses under the erosion-corrosion test compared to those under the erosion test at all impact angles.
RESUMO
In this research, the effect of water-silica slurry impacts on polylactic acid (PLA) processed by fused deposition modeling (FDM) is examined under different conditions with the assistance of an adaptive neuro-fuzzy interference system (ANFIS). Building orientation, layer thickness, and slurry impact angle are considered as the controllable variables. Weight gain resulting from water, net weight gain, and total weight gain are the predicting variables. Results uncover the accomplishment of the ANFIS model to appropriately appraise slurry erosion in correlation with comparing real data. Both experimental and ANFIS results are almost identical with average percentage error less than 5.45 × 10-6. We observed during the slurry impacts tests that all specimens showed an increase in their weights. This weight gain was finally interpreted to the synergetic effect of water absorption and the solid particles fragmentations immersed within the specimens due to the successive slurry impacts.
RESUMO
In this work, two new αâ¯+â¯ß titanium alloys with low contents of ubiquitous and low-cost alloying elements (i.e., Mo and Fe) were designed on the basis of the electronic parameters and molybdenum equivalent approaches. The designed Ti - 2Mo - 0.5Fe at. % (TMF6) and Ti - 3Mo - 0.5Fe at. % (TMF8) alloys were produced using arc melting process for studying their mechanical, electrochemical and cytotoxicity compatibilities and comparing these compatibilities to those of Ti-6Al-4V ELI alloy. The cost of the used raw materials for producing the TMF6 and TMF8 alloys are almost 1/6 of those for producing the Ti-6Al-4V ELI alloy. The hardness of the two alloys are higher than that of the Ti-6Al-4V ELI alloy, while their Young's moduli (in the range of 85-82â¯GPa) are lower than that of the Ti-6Al-4V ELI alloy (110â¯GPa). Increasing the Mo equivalent from 6 (in TMF6 alloy) to 8 (in TMF8 alloy) led to an increase in the plastic strain percent from 4% to 17%, respectively, and a decrease in the ultimate tensile strength from 949â¯MPa to 800â¯MPa, respectively. The microstructure of TMF6 alloy consists of α'/αâ³ phases, while TMF8 alloy substantially consists of αâ³ phase. The corrosion current densities and the film resistances of the new alloys are in the range of 0.70-1.07â¯nA/cm2 and on the order of 105â¯Ω·cm2, respectively. These values are more compatible with biomedical applications than those measured for the Ti-6Al-4V ELI alloy. Furthermore, the cell viabilities of the TMF6 and TMF8 alloys indicate their improved compatibility compared to that of the Ti-6Al-4V ELI alloy. The CCK-8 (Cell Counting Kit-8) assay was conducted to investigate the cytotoxicity, proliferation, and shape index of the cells of the candidate alloys. Overall, the measured compatibility of the new V-free low-cost alloys, particularly TMF8, makes them promising candidates for replacing the Ti-6Al-4V ELI alloy in biomedical applications.
