Effect of Processing Parameters on Compressive Behavior of Ti Foams

Abstract

Among metal foams, titanium (Ti) and its alloys are very attractive since they combine unique properties such as high strength-to-weight ratio, excellent corrosion resistance and biocompatibility. This study presents a relatively cheap processing route such as sintering with fugitive space holders in an Ar gas atmosphere and reveals the relationship between microstructure and compressive behavior. Removal of the space holder was conducted either by heat treating at a temperature determined by the TG-DTA analysis, or by dissolution in hot deionized water. When carbamide is removed thermally, removal temperature should be chosen carefully to avoid reaction with Ti. Removal by dissolution in water renders it possible to minimize contamination of Ti. Contamination was further reduced by using magnesium (Mg) and Ti sacrifices, and shielding. Porosities and elastic moduli between 5 - 75 % and 4 - 25 GPa, respectively, were achieved. Pore sizes varying between a few mu m up to 2 mm were obtained. Compressive test results indicated that needle-like pores cause some decrease in elastic modulus and yield strength when compared to spherical pores. Additionally, FGMs with graded porosity and pore size were easily produced.