Novel approach for fabrication and characterisation of porosity-graded material

A novel continuously graded material that is based on a porosity-graded structure was successfully synthesised via a cold pressing-vacuum sintering-dissolution process (SDP) of powder metallurgy technology. Microscopic observations and the Archimedes method were used to confirm the newly synthesised porosity-graded material, the mechanical properties and the modulus. The results show that the density continuously increased from 1.4 to 2.7 g cm(-3), and there was no obvious interfacial transition layer. In addition, the hardness and elastic modulus were obtained from nanoindentation tests and display a stepwise feature along the gradient direction. Moreover, we found that the fractography changes from typical ductile fracture to ductile and cleavage fracture with an increase in the porosity. [GRAPHICS] .