Fabrication of Ti-Al micro/nanometer-sized porous alloys through the kirkendall effect

A novel technique, based on the Kirkendall effect, to fabricate Ti-Al micrometer/nanometer-sized porous alloys with adjustable pore sizes ranging from several tens of micrometer to several tens of nanometers were introduced. Kirkendall pores impact negatively on the mechanical properties, so that significant efforts have been devoted to remove these pores for engineering applications. The crystal structures of compacts before and after the sintering processes were studied by using X-ray diffraction (XRD). The open porosity and maximum pore size have also been determined by the Archimedes method and by a combination of the bubble point method and scanning electron microscopy (SEM) estimation, respectively. The pore distribution curves for all porous structures were measured by the liquid-extrusion method. SEM investigations revealed that the porous structures can also be altered by the size of Ti/Al powders, the cold pressing pressure, and the sintering temperature.