亜鉛合金のポロシティ生成に及ぼす溶存ガスの影響 Effect of Dissolved Gases on Porosity Formation of Cast Zinc Alloy
Zn-4Al-3Cu-0.05Mg cast alloy is used in mold manufacturing for prototyping, but seldom in mass production due to surface defects. One of its main causes, the effects of dissolved gasses were investigated. The volumetric fraction of porosity in the castings obtained in different gas atmospheres decreased in the following order : oxygen, hydrogen, air, argon. Analysis using galvanic cells based on solid electrolyte and a direct measurement of oxygen potential on solidification indicated that the gas liberated at solidification was not oxygen but hydrogen. The hydrogen content in the molten alloy was also measured by the Telegas measurements and Sievert’s parameter, and it showed a good agreement with that from the volumetric fraction of porosity. It is demonstrated that concentrated hydrogen in front of the fluid-solid interface is one cause of micro-porosity formation.
- 鋳造工学 = Journal of Japan Foundry Engineering Society
鋳造工学 = Journal of Japan Foundry Engineering Society 69(8), 635-642, 1997-08