نمونه سوالات آزمون های کارشناسی ارشد مهندسی مواد و متالورژی زبان عمومی و تخصصی (انگلیسی) امتحانات 94-86 - بخش (2)

Virtually all important properties of solid materials may be grouped into six different catogories: mechanical, electrical, thermal, magnetic, optical and deteriorative. For each there is a characteristic type of stimulus capable of provoking different responses. Mechanical properties relate deformation to an applied load or force; examples include elastic modulus and strength. For electrical properties, such as electrical conductivity and dielectric constant, the stimulus is an electric field. The thermal behavior of solids can be represeuted in terms of heat capacity and thermal conductivity. Magnetic properties demonstrate the response of a material to the application of a magnetic field. For optical properties, the stimulus is electromagnetic or light radiation; index of refraction and reflectivity are representative optical properties. Finally, deteriorative characteristics relate to the chemical reactivity of materials. In addition to structure and properties, two other important components are involved in the science and engineering of materials-namely, "processing" and "performance". With regard to the relationships to these four components, the structure of a material will depend on how it is processed. Furthermore, a material`s performance will be a function of its properties.