气体压力和熔体过热度通过决定熔体中气体溶解量而直接影响多孔试样的气孔率。本文通过理论分析建立了固/气共晶定向凝固中气体逸出和藕状多孔结构形成所需的过热度和气体压力判据。以金属/氢气共晶为例，计算结果表明，过热度和氩气分压均应有一适中的范围：给定氢气和氩气分压时，过热度应高于藕孔形成临界过热度而低于氢气逸出临界过热度；给定过热度和氢气分压时，氩气分压应高于氢气逸出临界氩气分压而低于藕孔形成临界氩气分压。该分析结果从藕状多孔Mg的实验结果得到了验证，可以作为高质量规则多孔材料实际制备过程的工艺参数指导原则。
Among all the processing parameters which affect porous structure obtained by directional solidification of a solid/gas (e.g. metal/hydrogen) eutectic (Gasar), the gas pressure above melts and the superheating temperature of melts are the most observable and easily governed because they directly control the amount of hydrogen saturated in melts. The critical processing conditions for hydrogen to escape and for formation of lotus-type porous structure have been deduced through theoretical analysis and calculation, and the following conclusions have been obtained: both the superheating temperature and the argon partial pressure should have moderate values, viz. with given partial pressures of hydrogen and argon, the superheating temperature should be bigger than the threshold of formation of lotus-type structure and smaller than that of hydrogen to escape; however, with given superheat degree and hydrogen partial pressure, the argon partial pressure should be bigger than the threshold of hydrogen to escape and smaller than that of formation of lotus-type porous structure. These conclusions were verified by the experimental results of lotus-type porous Mg and will contribute to the fabrication of high-quality regular porous metals by Gasar process.
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