MATERIALS SCIENCE AND ENGINEERING

Materials science, also commonly known as materials engineering, is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This relatively new scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. Materials engineers deal with the science and technology of producing materials that have properties and shapes suitable for practical use. Activities of these engineers range from primary materials production, including recycling, through the design and development of new materials to the reliable and economical manufacturing for the final product. Such activities are found commonly in industries such as aerospace, transportation, electronics, energy conversion, and biomedical systems. The future will bring ever-increasing challenges and opportunities for new materials and better processing. Materials are evolving faster today than at any time in history. Quality products result from improved processing and more emphasis will be placed on reclaiming and recycling. For these many reasons, most surveys name the materials field as one of the careers with excellent future opportunities. Besides new physics emerge because of the diverse new material properties which need to be explained.

Solid materials have been conveniently grouped into three basic classifications: metals, ceramics, and polymers. This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or another, although there are some intermediates. In addition, there are three other groups of important engineering materials—composites, semiconductors, and biomaterials. Composites consist of combinations of two or more different materials, whereas semiconductors are utilized because of their unusual electrical characteristics; biomaterials are implanted into the human body. Metallic materials are normally combinations of metallic elements. They have large numbers of non-localized electrons; that is, these electrons are not bound to particular atoms. Many properties of metals are directly attributable to these electrons. Metals are extremely good conductors of electricity and heat and are not transparent to visible light; a polished metal surface has a lustrous appearance. Furthermore, metals are quite strong, yet deformable, which accounts for their extensive use in structural applications.

Ceramics are compounds between metallic and nonmetallic elements; they are most frequently oxides, nitrides, and carbides. The wide range of materials that falls within this classification includes ceramics that are composed of clay minerals, cement, and glass. These materials are typically insulative to the passage of electricity and heat, and are more resistant to high temperatures and harsh environments than metals and polymers. With regard to mechanical behavior, ceramics are hard but very brittle. Polymers include the familiar plastic and rubber materials. Many of them are organic compounds that are chemically based on carbon, hydrogen, and other nonmetallic elements; furthermore, they have very large molecular structures. These materials typically have low densities and may be extremely flexible. A number of composite materials have been engineered that consist of more than one material type. Fiberglass is a familiar example, in which glass fibers are embedded within a polymeric material. A composite is designed to display a combination of the best characteristics of each of the component materials. Fiberglass acquires strength from the glass and flexibility from the polymer. Many of the recent material developments have involved composite materials.

Semiconductors have electrical properties that are intermediate between the electrical conductors and insulators. Furthermore, the electrical characteristics of these materials are extremely sensitive to the presence of minute concentrations of impurity atoms, which concentrations may be controlled over very small spatial regions. The semiconductors have made possible the advent of integrated circuitry that has totally revolutionized the electronics and computer industries (not to mention our lives) over the past two decades. A biomaterial is any matter, surface, or construct that interacts with biological systems. As a science, biomaterials is about fifty years old. Biomaterials science encompasses elements of medicine, biology, chemistry, tissue engineering and materials science. Biomaterials can be derived either from nature or synthesized in the laboratory using a variety of chemical approaches utilizing metallic components, polymers, ceramics or composite materials. They are often used and/or adapted for a medical application, and thus comprise whole or part of a living structure or biomedical device which performs, augments, or replaces a natural function. These materials must not produce toxic substances and must be compatible with body tissues (i.e., must not cause adverse biological reactions).

3. Запомните необходимый минимум профессиональной лексики:

Задание II

1. Определите по формальным признакам, какой частью речи являются следующие слова, и переведите их:

Relatively, conversion, excellent, opportunity, distinct, particular, electricity, passage, polymeric, flexibility, recent, conductor, circuitry

2. Найдите в тексте прилагательные с суффиксами – al,

- able, -ible и переведите их.

Задание III

1. Подберите эквиваленты к глаголам, обозначенным цифрами:

2. Подберите эквиваленты к словосочетаниям, обозначенным цифрами:

3. Соотнесите термины с их определениями:

3. Заполните пропуски, используя предложенные слова:

Resistant, nature, challenges, insulative, structure, fiberglass

1. The future will bring a lot of … and opportunities for new materials.

2. Classification of solid materials is based primarily on atomic ….

3. Cement and glass are … to the passage of electricity and … to high temperatures.

4. In … fibers are embedded within a polymeric material.

5. Biomaterials can be derived from … or synthesized in the laboratory.

Задание IV

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