Characterizing Porous Titanium Alloy Microstructure

An optical microscope (Olympus DP74, Olympus America Inc., United States) was used to observe the structure and surface morphology of the sample. A scanning electron microscope (FEI, XL30-FEG, United States) was used to qualitatively observe the micromorphology of the porous titanium alloy (surface morphology and connectivity). A suitable photo was captured to observe each sample from three selected fields of view; ten values were measured in each field, and the mean pore size was calculated. The calculation method of the porosity of each porous sample was as follows: the volume density (q) of the sample was determined by measuring the physical size and mass of the sample; the Archimedes principle was used to measure apparent density (q') in water. The metal volume fraction (VF) was calculated as follows: VF = q/q'. Porosity PP = 1−VF = 1−(q/q'). According to the method reported by Hotaling (Hotaling et al., 2015 (link)), the ImageJ software (National Institute of Health, Bethesda, United States) was used to calculate the wire diameters of the two porous materials.