Evaluation of Porosity in Lotus--Type Porous Cu Fabricated with Gasar Process

Lotus-type porous Cu with elongated pores has been fabricated by a unidirectional solidification method under a pressurized hydrogen or gas mixture of hydrogen and argon. Through solving the steady-state solute distribution function in the front of the solidification interface, the hydrogen content in the solid metal was calculated and a new theoretical model for calculating porosity was founded. Solidification rate and the diffusivity of hydrogen were taken into account and the predicted porosity values are in good agreement with the experimental results under different partial pressures of hydrogen and argon. In addition, the relationship between porosity and partial pressures of mixed gases was obtained.