Материаловедение: свойства металлов. Матросова Т.А - 10 стр.

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УлГТУ | Ульяновск

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образом обычно определяют макроскопические параметры материала? 6. Чем
определяются микроскопические свойства материалов? 7. Какие уровни
познания можно выделить с целью соотнесения микро- и макропараметров? 8.
Какая дисциплина объясняет поведение микрочастиц? 9. Поведение каких
объектов описывает теория относительности? 10. Приложима ли теория
относительности к малым частицам и при каких условиях? 11. Какое значение
имеет теория относительности для инженера
-механика в части изучения
свойств материалов?
Topic 3. Mechanical Properties of Materials
Designers and engineers are usually more interested in the behavior of
materials under load or when in a magnetic field than in why they behave as they do.
Yet the better one understands the nature of materials and the reasons for their
physical and mechanical properties the more quickly and wisely will he/she be able to
choose the proper material for a given design. Generally, a material property is the
measured magnitude of its response to a standard test performed according to a
standard procedure in a given environment. In engineering materials the loads are
mechanical or physical in nature and the properties are recorded in handbooks or, for
new materials, are made available by the supplier. Frequently such information is
tabulated for room-temperature conditions only, so when the actual service conditions
are at subfreezing or elevated temperatures, more information is needed.
All materials have properties that designers must use to their best advantage.
The following terms describe these properties:
Ductility is a softness present in some materials, such as copper and
aluminum, that permits them to be formed by stretching (drawing) or hammering
without breaking. Wire is made of ductile materials that can be drawn through a die.
Brittleness is a characteristic of metals that will not stretch without breaking,
such as cast irons and hardened steels.
Malleability is the ability of a metal to be rolled or hammered without
breaking.
Hardness is the ability of a metal to resist being dented when it receives a
blow.
Toughness is the property of being resistant to cracking and breaking while
remaining malleable.
Elasticity is the ability of a metal to return to its original shape after being
bent or stretched.

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