DISCOVERING ABLATION

摘要

An emerging technology known as ablation can achieve fine microstructure and better mechanical properties in casting alloys. Similar to ablation of ice glaciers, where the snow and ice accumulated in the winter months is worn away in the summer by melting, erosion, evaporation and sublimation ablation casting erodes away the sand and binder of a sand mold. In this emerging casting method, the mold is sprayed with a liquid and/or gas solvent directly after pouring. As the solvent dissolves (or ablates) the sand mold, it facilitates rapid heat removal to solidify the molten alloy quickly (Figs, 1a &, 1b). The rapid solidification achieved through ablation enhances the mechanical properties of the casting alloys. While only a few facilities have ablation casting capabilities, the emerging method has been successfully used for conventional aluminum alloys in commercial production and stood up well against other emerging magnesium casting methods in a comparison study. Due to its ability to achieve fine microstructure and low tendency for hot tearing, the new process has opened up possibilities for casting typically difficult-to-cast alloys. As part of the exploration of ablations potential benefit to casting technology, researchers have studied its ability to produce wrought castings as well as aluminum metal matrix composites (MMCs).