Material Components, Processing, Applications

A review of alloy and process development of the TiAl alloy has been published by Wu (2006). The main conclusions are that TiAl development is now relatively mature the major requirement is the promotion of low cost processing coupled with the supply of high-quality raw material the future application of net shape powder process routes could be cost effective both for complex large components and for some small components. Special attention is dedicated in this review to alloys based on Ti-(45—46)Al-(5-8)Nb (at.%) and Ti-48Al-2Cr-2Nb (at.%). 

Carbon nanotubes comprise a very promising material for various applications and especially as an active component in composites and hybrids as will be documented in the other chapters of this book. Harnessing these nanoscopic assets in a macroscopic material would maximize CNTs potential and applicability. The choice of synthesis technique and purification method, which define size, type, properties, quality and purity of CNTs as well as their processability, is crucial for their implementation into composites and hybrids. 

Modern C3 materials for automotive applications, such as components of the car body, are synthesized according to the flow scheme of Fig. 9.2. Here an integrated synthesis of both filler and binder components is taken as a cost-effective approach. In high-tech applications it is more customary to independently optimize the preparation of the fiber component [15,19, 20, 36, 37] and then the C3 synthesis in separate processes with extensive quality control measures in-between. 

There are no simple rules of thumb in defining the cost of reinforced plastic components. Their successful use has resulted from proper design, utilizing the benefits these materials offer, process selection, tooling cost advantages that fit the production needs, and consideration of life cycle economics. Each existing application illustrates the cost-performance advantage of reinforced plastic over the traditional material that is displaced. 

The fuel cells are still too expensive for most applications (several thousand US Dollars per kW). This is due to the amount and kind of materials, manufacturing processes and manufacturing volumes. The most critical components are the catalyst and the membrane materials. Pt loading in today s fuel cells is typically around 0.3 mg/cm2 of electrode active area, which corresponds to 0.6 mg/peak Watt (or 0.6 g/kW). The cost of the membrane material is expected to decrease by half for every two orders of magnitude increase in manufacturing volume. 

In the last 10 years, significant advances in fibrous monolithic ceramics have been achieved. A variety of materials in the form of either oxide or nonoxide ceramic for cell and cell boundary have been investigated [1], As a result of these efforts, FMs are now commercially available from the ACR company [28], These FMs are fabricated by a coextrusion process. In addition, the green fiber composite can then be wound, woven, or braided into the shape of the desired component. The applications of these FMs involve solid hot gas containment tubes, rocket nozzles, body armor plates, and so forth. Such commercialization of FMs itself proves that these ceramic composites are the most promising structural components at elevated temperatures. 

Whisker-reinforced glass-ceramic matrices are expected to find several applications in automotive components, metal forming, cutting tools, etc., due to their low thermal expansion, high thermal shock resistance, high reliability and low material and processing costs. Some industrial applications for continuous fibre-reinforced ceramic matrix composites (CMCs) are listed below. 

A 2-phase program was conducted. The first phase was a materials and process study. The second phase dealt with the manufacture of a selected high-performance weapon component in prototype quantity to demonstrate the applicability of the developed PM forging process. A processing specification and an economic evaluation of the developed manufacturing process also was included... 

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