Compressive Properties And Energy Absorption Of Porous Titanium

Porous titanium presents higher corrosion resistance and strength than other metallic porous materials and has found a variety of applications in filtration separation,energy absorption and heat transfer.In this study,porous titanium was fabricated by compact and vacuum sintering of two raw materials,TiH2 powder and Ti-6Al-4V fiber,separately.During sintering,different percentage of NaCl was used as pore-forming agent for porous titanium fabricated by TiH2 powder.Pore structure of porous titanium was observed by optical microscope microscopy and scanning electron microscopy.The influence of addition of pore-forming agent and compacting pressure on the porosities of porous titanium fabricated by powder was studied.Diameters of fibers and compacting pressure on the porosities of porous titanium made by fiber were also evaluated.In addition,the influence of porosities and sintering temperature on compressive properties of these two porous titanium,including compressive strength and energy absorption,were systematically studied using universal testing machine.The following conclusions can be made:(1)The porosities of porous titanium fabricated by powder increase linearly with increasing addition of NaCl,and the porosity of this porous titanium can reach 86.4%.However,the influence of compacting pressure on porous titanium fabricated by powder can be neglected.With a decrease of compacting pressure,the porosities of porous titanium fabricated by fiber show an increasing trend.In addition,with a decrease of fiber diameters,the porosities decreased slightly but the distribution of these fibers become more uniform.The difference between the porous titanium fabricated by powder and fiber is the pore structure,which is dual pore structure for the former and single pore structure for the latter.(2)Increasing the sintering temperature can improve the development of the sintering neck and increase the compressive properties of the porous titanium.It was found that at 900?,porous titanium was in the early stage of sintering.At 1200?,the porous titanium is in the late stage of sintering.(3)When the porosity and sintering temperature is nearly the same for porous titanium fabricated by powder and fiber,porous titanium fabricated by powder offers higher compressive strength(124.5 MPa)than porous titanium fabricated by fiber(29.5MPa),larger energy absorption(61.3MJ/M3 vs.13.9 MJ/M3)and similarly energy absorption efficiency(63.65 vs.66.9%).In summary,the compressive strength and energy absorption of porous titanium fabricated by powder are higher than that of porous titanium fabricated by fiber in the same condition.Therefore,porous titanium fabricated by powder is more applicable to be used in load bearing and energy absorption area.