Directional solidification of metal/gas eutectic (Gasar) is a novel process for fabricating porous metals with oriented pores parallel to the solidification direction. By use of the developed Gasar apparatus, porous magnesium samples with different porosities have been fabricated. In addition, this paper also studied the effects of gas pressure on porosity, pore nucleation, pore size and distribution.

The iron resource efficiency, for defining the degree of saving of natural iron resources in steel production process, was formulated. A standard iron--flow diagram of steel production process was given. The influences of iron--flow deviated in various ways from standard iron--flow diagram on iron resource efficiency were analyzed. The relationship between iron resource efficiency of steel production process and of its unit process has also been discussed. By using the data of a steel plant, the influences of iron--flow in steel production process on its iron resource efficiency were analyzed as an example.