Gépészet 2000 1-2. [antikvár]

TÍÍE \KKI> FOR MA IKRIALS IN THE EARLY TWOTHOLSANDS •lo/sef Ciyulai Professor, Res Inst, for Tech. Phys. and Mall. Sci. and Chair for Hxper. Phys., Tech. Univ. Budapest POFJox 49,11.1525 Budapest, phone: (36-1) 395-9253, email: gvulai^ä'mfa.kfki.hu Summary Mai ('rials, the horizontal scction of almost all sciences, also enter into a new era. Energy and mitlenals considerations are becoming the highest priority with process simulation as a demand. Def inition for structural and functional matenals is proposed and the front lines of nuiterials research are reviewed. Examples for miniaturization are given for micro- and nanolechnology. I INTkODlJiHON Materials sciciicc entered, and even is in the move of entering into a new era. At a conference on machine engineering, it is important to point out that materials were tested in the practice, ;nul this "practice" is called since a few centuries as machine engineering. Thus, the two ilisciplines were developing in close interaction. In the 19"' and 20'^ century, more and more qiianlilative knowledge accumulated in tlie field of materials. More and more knowledge pioduccd l>y physics, chemistry infiltrated and fertilized the earlier experience based mclalliirgy, glass blowing, production of ceramics, as most important fields of so-called sliuclural materials. Atiother family of materials, which arc called functional materials, was developing lirsl in silence. Discovery of magnetism, electricity and current, photoelectricity, double optical refraction, etc. were curiosities first, but in the 19'^ century, this trend has changed. The first big jump changing human life profoundly was the expanding use of eleclricity. The ne.\t one was the onset of electronics, which, with the discovery of the irausislors. resulted llie era of information technology. This has caused an enonnous change in nialeriais science through its demands in the family of functional materials. As lieliuitions of the iwo materials families are somewhat ambivalent, the following distinction will be proposed here. Structural materials find application as a consequence of their favorable bulk properties, first of all. of their mechanical properties, like hardness, elastic properties, etc. Wear and, often, corrosion resistance is an additional property demanded in applications. Sometimes, as a special need, oilier consequcnees of defect generation are involved, e.g., a stability of the properties when subjected to irradiation, This is called radiation hardness. In (he ease funciional materials, "responses" of the material to other external effects than ineehanieal forccs. are characteristic. The "external effect" can be of electrical, magnetic, optical. gr.i\ii.uional. etc. origin, but other interactions are also included, e.g., particle boml\irdmcnt. interaction with molecules at its surtace, isotopic effects, i.e., practically any atonue level niteraetion with the matter. The response of the matter is also diverse. It can respond witli changes its eleetrical. magnetic, mechanical, optical behavior, etc. .Almost any interaction that pliysics. chemistry, biology studies, characterizes the material as functional and it is the scientists' and engineers' imagination only that limits the legion of utilization. In \ast maiorit) of cases, the functional materials exhibit not only changes of a single property