Title Introduction in Materials Science and Engineering

MATERIALS SCIENCE AND ENGINEERING

Materials science involves investigating the relationships that exist between the structures and properties of materials.

Materials engineering is, the basis of these structure–property correlations, designing or engineering the structure of a material to produce a predetermined set of properties. 

So what Structure and property means?

The Definitions of Structure

Structure, the structure of a material usually relates to the arrangement of its internal components.

Subatomic structure involves electrons within the individual atoms and interactions with their nuclei.

On an atomic level, structure encompasses the organization of atoms or molecules relative to one another.

The next larger structural realm, which contains large groups of atoms that are normally agglomerated together, is termed ‘‘microscopic’’

Finally, structural elements that may be viewed with the naked eye are termed ‘‘macroscopic.’’

The Definitions of property

Definitions of properties are made independent of material shape and size. Property  is  a  material  trait  in  terms  of  the  kind  and magnitude  of  response  to  a  specific  imposed  stimulus.

All important properties of solid materials may be grouped into six different categories: mechanical, electrical, thermal, magnetic, optical, and deteriorative.

 Mechanical properties relate deformation to an applied load or force; examples include elastic modulus and strength.

• Electrical properties, such  as  electrical  conductivity  and  dielectric  constant,  the  stimulus  is  an  electric field.
•  The thermal behavior of solids can be represented in terms of heat capacity and thermal conductivity.
• Magnetic properties, demonstrate the response of a material to the application of a magnetic field.
• Optical properties, the stimulus are electromagnetic or light radiation; index of refraction and reflectivity are representative optical properties.
• Finally, deteriorative characteristics indicate the chemical reactivity of materials

  In addition to structure and properties, two other important components are involved in the science and engineering of materials, viz. ‘‘processing’’ and ‘‘performance"
The structure of a material will depend on how it is processed. And material’s performance will be a function of its properties. So the interrelationship between processing, structure, properties, and performance is linear.

Processing >>>>>> Structure >>>>>>> Properties >>>>>>> Performance

WHY STUDY MATERIALS SCIENCE AND ENGINEERING?

Before we study this question we should answer, why do we study materials?

Many an applied scientist or engineer, whether mechanical,  civil,  chemical,  or  electrical,  will  at  one  time  or  another  be  exposed  to  a design problem involving materials, materials  scientists  and  engineers  are  specialists  who  are  totally involved in the investigation and design of materials.

So the material selection of many thousand of materials may be a critical problem in which reaching to the final decision. First of all the in-service conditions must be characterized in order to dedicate the required properties of the material, in rare situations the material have the maximum combination of properties so we must trade off one characteristic for another, the classic example is the strength and ductility, whenever high strength material posses limited ductility and vise versa .secondly the expected failure during the operation of the material e.g. significant reductions in mechanical strength may result from exposure to elevated temperatures or corrosive environments. Finally, probably the overriding consideration is that of economics: What will the finished product cost?