Abstract: Devices comprising a component which has an open porous structure composed of an alloy of nickel and titanium or a mixture of nickel and titanium. The devices can be implanted in a mammalian body and provide desired interaction with protein, blood, ions, bone cells, and tissue. The devices are particularly useful for providing a substrate for the ingrowth of bone. In the open pore structure, preferably more than 95% of the pores having a size of 50-1000 ?m, particularly 50-600 ?m, with a pore size standard deviation of 250 ?m or less, particularly of 150 ?m or less, and an average porosity by volume of 40-80%. When the device is implanted adjacent to a cancellous bone, the porous component preferably has a modulus of 0.1-1.2 GPa. When the device is implanted adjacent to cortical bone, the porous component preferably has a modulus of 16 to 24 GPa. The devices are also useful for filtering a liquid.