Papers by Keyword: Mold-Casting

Abstract: Lotus-type porous magnesium ingots were fabricated in pressurized hydrogen atmosphere through a mold casting technique. The mold consists of two cooling blocks placed at the bottom and one lateral side. It was found that the pores started to grow upwards and horizontally and the both directional pores collapsed and then shifted to the direction. Such anisotropic growth of pores is in good agreement with the map of temperature gradient predicted by two-dimensional finite differential analysis.

Abstract: Recently, Ti-based metallic glasses aim at biomaterials with their high specific strength and superior corrosion resistance. Their high workability also shows a good performance for mass production under the energy saving environment. In this study, we started investigation of the design of Ti-based metallic glasses with the restricted alloying elements for biocompatibility and characteristic evaluation of the optimized Ti-based metallic glasses with higher glass forming ability for dental implants. These Ti-based metallic glasses do not contain Al, V and Ni elements which are well known to be neurotoxicity and cytotoxicity for human body. Current medical reports of impracticability by these elements have been a hot issue in biomaterials science. Newly designed Ti-based metallic glasses exhibit good performances. Especially, the optimized Ti-based metallic glass has high corrosion resistance with better passivity in a wide passivation range in simulated body fluids at 310K. In addition, biocompatibility of Ti-based metallic glass was also evaluated by cell culture in vitro. Excellent biocompatibility of Ti-based metallic glass show high potentials to be applied as biomaterials that necrosis of osteoblast (SaOS2) was not detected in this study.

Abstract: A Zr65Al7.5Ni10Cu17.5-xPdx (x=0-17.5 at. %) alloy system is found to exhibit a different dependence of glass-forming ability (GFA) on atmosphere-pressure during mold casting process. High-Pd alloys (x=7.5-17.5) show a remarkable increase of critical size for glass formation (dc) as casting-atmosphere (Ar) pressure varies from vacuum to ambient. No significant change of dc, however, is observed in low-Pd alloys (x=0-5) despite the variation in atmosphere pressure. The origin of the phenomenon is unveiled by correlating the cooling characteristic during mold casting and on-cooling phase transformation characteristic of the alloy system.