What are the properties of materials?

The economists are mainly concerned causes the industries manufacturing engineering materials are interested in which the engineering materials can be used or applied in the best economic way. The economist should have a working knowledge of the properties and manufacturing processes of various engineering materials.

The fields of application of a particular engineering material are governed by the characteristics and various properties of that engineering material.

• Chemical properties:- The chemical properties of the material suggest the tendency of the material to combine with other substances, its reactivity, solubility, and effect like corrosion, chemical composition, acidity, alkalinity,  etc. Corrosion is one of the serious problems faced by engineers in selecting engineering materials, caused due to the chemical properties of the metal. In metals, valance electrons are loosely bound to their atoms and can be easily removed during chemical reactions. So, when metals are exposed in the atmosphere and come in contact with gases like oxygen, chlorine etc., the chemical reactions take place. When iron reacts with oxygen, iron oxide is formed which is red in colour and iron metal is coated with it. It is called corrosion.

                                 

• Electrical properties:- These properties signify the ability of the material to resist the flow of an electric current and they include conductivity, dielectric strength and resistivity.
• Magnetic properties:- The study of magnetic properties of the material to resist the flow of an electric current and they include conductivity, dielectric strength and resistivity. 
• Mechanical properties:-The characteristics governing the behaviour of a material when external forces are applied are included in these properties. Some of the important mechanical properties are elasticity, hardness, plasticity, strength, etc.
• Optical properties:-When the material is to be used for the optical work, the knowledge of its optical properties like colour, light transmission, refractive index, reflectivity, etc. is necessary. When light strikes any material, it interacts with its atoms and causes various types of effects. The light .aye be either reflected, refracted, scattered or absorbed. The study of light in materials and how to use this behaviour to control the various light effect is called optics.
• Physical properties:-These are required to evaluate the conditions of the material without any external force acting on it and they include bulk density, durability, porosity, etc.
• Thermal properties:-The knowledge of thermal properties of the material like specific heat, thermal expansion and conductivity are helpful in knowing the response of the material to the thermal changes. Thus suitable materials can be selected to withstand fluctuating and high temperatures.
• Technological properties:- The properties of metals and alloys which have a bearing on their processing or application are called technological properties. Castability, machinability, weldability and workability are some of the significant technological properties of metals and alloys.

     Out of all such properties, the physical properties and mechanical properties are particularly very important to a construction engineer.