Thixomolding is known for its effective process control, microstructural engineering and property enhancement. The potential benefits from its application for net shape forming of magnesium alloys have been emphasized previously [1]. It was proven that the technique is competitive when the parts require high integrity, intricate design, often combining thin and thick sections, or there is an opportunity to reduce or eliminate machining. The benefits are associated, first, with the semisolid state of the alloy, having a high and controllable viscosity which promotes the non-turbulent filling of the mold. Secondly, the molding effectively combines the slurry making and part-forming operations into a one-step process and the facility is freed from having to deal with the transport of the liquid metal. The closed environment provides better protection of the semisolid alloy against oxidation than that offered by a conventional furnace; a factor of greater importance for magnesium alloys, having an extremely high affinity to oxygen [2]. Experiments with a prototype revealed that the machine represents a universal and multitask processing unit. Since the heating system assures precise temperature distribution along the alloy flow path and control of the alloy transformations in a semisolid state, it is possible to create a variety of unique microstructures which result in valuable properties. Examples of utilizing these capabilities for manufacturing components from magnesium alloys are described in this article.
展开▼
