New Materials in Mechanism
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New Materials in Mechanism
 
Article Introduction
In the face of rapid advances in the development of the materials discovered, the fundamental knowledge regarding the connection between material properties and the atomic structure of the material was secured until the mid-nineteenth century. Only in the course of new discoveries in the areas of physics and chemistry was the systematic investigation of material properties using scientific methods possible.

Article Description
The significance of Latest Materials
Nowadays, physicists, chemists and engineers carry out materials research in interdisciplinary teams. Previously, materials were developed and then an application for them; today, materials are designed on the basis of the requirements of the technical systems in which they will be used. This means, however, that the results of the development of traditional materials and the potential of new materials are often overshadowed by the finished product and are hidden, despite their fundamental importance to technical innovation and economic progress, i.e., materials no longer play an independent role.

New materials increasingly provide the force for system innovations. They are thereby key and pacemaker technologies for technological progress in the sectors of mechanical engineering, medical technology, transportation, energy, and information technology. The added-value potential of new materials must be judged in connection with the systems or products that are made possible through their development.

Metallic Materials
Many applications in mechanical engineering, aerospace, and in the automotive industry demand materials of low weight combined with high strength and toughness. The performance potential of conventional materials has not yet been fully exploited in many areas; even classical metallic alloys based on iron, nickel, cobalt, aluminium, titanium, copper, and magnesium will be developed further. Development trends for new metallic materials go hand in hand with developments in process technology, enabling economical, ecological, and technically meaningful production of these materials. Examples of such production trends are the "micro structural engineering" of multiphase steels, e.g.. Duplex steels and micro alloying techniques.

Aluminium will retain its importance as a lightweight construction material. Potential exists in the area of recycling, which requires 95% less energy than the production of primary aluminium. However, if aluminium is mixed with materials from which it cannot be separated, it must be excluded from the recycling process. The goal is to keep this proportion as low as possible. In titanium alloys, components with considerably higher complexities are now possible thanks to improved production techniques, e.g. through super plastic forming, as well as through much larger castings with homogenous properties in large cross sections. The considerably higher material costs compared to those of steel or aluminium, significantly higher processing costs and inferior wear properties have, up to now, stood in the way of the more wide- spread use of titanium alloys.

There are global initiatives to develop a lightweight construction alloy for high temperatures from the class of intermetallic alloys on the basis of titanium aluminides. These alloys have great potential for applications in compressor blades of aircraft engines and stationary gas turbines, as well as for outlet valves of combustion engines. Insufficient oxidation resistance, limited strength and toughness, and high costs still hinder broader applications. However, the possible impact of such materials has been widely recognised and can be seen in the corresponding research projects that receive government support in many countries.

Open-cell metal foams (sponges) with pore structures that have been specifically incorporated are a new class of functional materials. The open-cell foamed metals are often produced by a modified investment casting process or with the help of foaming agents. The selection of alloys, geometry, density, and cell structure can thereby be specifically matched to the requirements of the component. This technique is used to reduce weight in vehicle construction, for catalysers, or in heat exchangers. Closed-pore foams can also be produced; these may be used for example in structural applications.

Ceramics
In addition to the classical applications of ceramics in insulators, porcelains, or sanitary goods, technical ceramics or high-performance ceramics are being increasingly used for applications in which metals and polymers have reached their limits. High levels of hardness and resistance to both wear and temperature are outstanding properties of ceramics. Despite intense research efforts, the fully ceramic combustion engine, which seemed feasible in the mid-1980s, has not yet been realizable. Ceramics have been successfully applied in automobile turbochargers and ceramic valves. The main goals of current research and development effort are to create more economical manufacturing procedures and to increase the reliability of ceramic components.

Polymers (Plastics)
The Age of Synthetic Materials began in 1869 with the discovery of celluloid. Sometimes referred to as "plastic", synthetic materials have become a synonym and a basis for progress and prosperity. The range of applications for synthetic materials continues to expand; the materials are often no longer visible to consumers within the product. High temperature-resistant thermoplastic open up applications that had previously been dominated by metals, glass, or ceramics, e.g. bearing application. Developments are aimed at making these materials even more affordable.

Intrinsically conductive polymer materials, the so-called organic metals have been researched for many decades, and could open up many new applications (e.g., heating tapes, fuse< sensors, etc). Promising starts have been made at the laboratory level; however, a breakthrough has not yet been achieved. Important research is also being one in the composting of biologically degradable polymers and polymer foams, which make cost-effective light-weight construction solutions possible, and which can be produced with environment-friendly foaming agents e.g. carbon dioxide.

Quasicrystals
Quasicrystals were discovered only twenty years ago. They were named "quasicrystals" because they show the properties of both periodic-crystalline and amorphous materials. They exhibit a high hardness, as well as high elasticity and plasticity. In addition, some compositions show low heat conductivity, which is why they also may be used as "metallic" thermal barrier coatings (e.g. on turbine blades). Other systems show non-stick properties-frying pans were the first commercial products to use these compounds as a surface coating. The said properties are also being tested in other applications, e.g. in preventing the formation of deposits in gas turbine compressors. It is still difficult to estimate the full potential of these materials.

Nanotechnology
Nanotechnology is not based on the development of new chemical combinations of materials. Instead - regardless of material groups - it leverages the change in properties of materials that arise, e.g. from the downscaling of micro structural features or particles into the nanometer range. It varies between visionary ideas that will be realised at the earliest in ten years and the production and launch of concrete first products. Much of the Nanotechnology research is still at a very basic stage.

There is a considerable amount of research focused on carbon nanomaterials. The first "Buckminster fullerene" - C60, the "bucky ball" - was discovered in 1985. It is the third main form of pure carbon alongside graphite and diamond. Since then, carbon nanotubes have also been discovered. Both nanostructures show qualities that promise great application possibilities. For example, the mixing of carbon nanotubes with rubber leads to a considerable increase in strength (ultra hard rubber). Nanotechnology has become an important driving force for future development in the research of new materials.
Posted : 8/12/2005

 
 
New Materials in Mechanism