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Vacuum-die casting offers a high-quality, low-cost alternative for manufacturing titanium components. Lower costs are obtained through the elimination of processing steps that are associated with other manufacturing methods, such as investment casting. However, vacuum-die-cast component geometry is limited to single-plane, solid components weighing less than 18 kg. Initial mechanical property tests performed on vacuum-die-cast Ti-6A1-4V show properties similar to that of wrought material, which could lead to the direct substitution of vacuum-die casting components for wrought components. Additionally, the quality of vacuum-die-cast components shows improvement over investment castings through the elimination of alpha-case and the use of a ceramic-less casting system.
INTRODUCTION
As titanium-casting usage for aerospace applications continues to rise, companies are looking for ways to lower costs by replacing higher cost titanium components manufactured by traditional methods,l especially in light of the intense competition in today's global economy. However, the replacement of forged titanium components with titanium castings must take into account the traditionally lower mechanical properties of castings.2 Therefore, a manufacturing process that offers lower costs and mechanical properties similar to wrought titanium could create significant opportunities for not only replacing existing titanium components, but in replacing components made from other materials as well.
Vacuum-die casting (VDC) was developed specifically for the purpose of providing a method for producing lowcost, high-quality titanium components. Typical applications for this process include airframe (i.e., bulkheads, brackets, wheels, and hinges), other aerospace, and commercial components.
DIE CASTING
Die casting has been used for many years in manufacturing low-cost, highvolume automotive and commercial components from Al-, Mg-, Zn-, and Cubased alloys. Die-cast components are made by melting the desired alloy in air and then injecting the molten metal, at high pressures, into a set of reusable dies containing the desired component geometry. Components made using this process are net-shape or near-net-shape, requiring minimal post-cast processing or machining to reach final...