Effects of pore size on the mechanical properties of three-dimensionally ordered macroporous nickel

The mechanical properties of three-dimensionally ordered macroporous (3DOM) nickel with pore sizes between 312 and 1200 nm are explored under nanoindentation and microhardness tester. This paper demonstrates that the hardness and elastic modulus of 3DOM Ni increase as the pore size decreases. The phenomenon that “smaller is stronger” is mainly due to the combined effects of sharing the load with more and smaller pore cells, the decrease of the moment upon the small pore wall and larger surface area to volume ratio. The deformation process of 3DOM Ni is pore wall “fracture-dominated” under nanoindentation while “bending-dominated” under microhardness tester. The results demonstrate how pore size control at the microstructural scale can tailor hardness and elastic modulus and hold great potential for the design and application of new 3DOM materials and devices.