In this article, we will discuss the Properties of Metals. Metals are defined as the element substances found in nature. They are available chemically combined with other elements. Metals are extracted from their ores.
Properties of Metals
The properties of the metal are defined as the special qualities or characteristics of metals that determine their suitability for a specific engineering application. Although metals have a wide range of properties, the knowledge of the important properties will be helpful in the section of the metals for a specific application. The properties of the metal are as follows
- Mechanical properties of metals
- Electrical properties
- Thermal properties
- Magnetic properties
- Chemical properties
Mechanical properties of Metal
The mechanical properties of metal indicate the nature of its inherent behavior under the action of external force. Or, we can say mechanical properties are the properties of the metal which are associated with its ability to resist failure under the action of external forces. Some of the most important Mechanical properties of the metal are as follows
Elasticity is the property of the metals by which they can regain the original shape and size after the removal of the load is called elasticity. It is a very important property, since all cutting tools and metallic objects maintain their original shape while working and after the removal of the applied force.
For every metal, there will be a maximum limit up to which the force applied will not leave any deformation after it ceases to exist. This maximum limit is called the elastic limit. If the Force is Applied beyond the elastic limit the metal will retain the deformation even after the removal of applied forces.
Plasticity may be defined as the property of metal by which a permanent deformation takes place without fracture whenever it is subjected to the action of external forces. Most of the metals have been found to possess good plasticity. This property is very important in forming and shaping an extruding operation.
Some metals are shaped in cold conditions, for example, deep drawing of sheets. Many metals are shaped in hot conditions, for example, the rolling of structural steel shapes and the forging of certain machine parts.
Ductility may be defined as the property of metals by which they can be drawn into wires or elongated before rupture takes place. This property depends largely upon tenacity and to some extent on hardness. The ductility of metal is higher when cold than hot, hence wires are drawn in cold conditions.
The following common metals have ductility in decreasing order Gold, Platinum, silver, iron, copper, aluminum, nickel, zinc, tin, and lead.
Brittleness may be defined as the property of metal under which it will fracture suddenly without any appreciable deformation. Less ductile metals will be brittle. Cast iron is one of the best examples of brittle metals.
Hardness may be defined as the property of metal by which resist, abrasion, indentation, and scratch by relatively harder materials. It is expressed related to the hardness of some standard minerals. Diamonds, quartz, corundum, etc. are the harder minerals.
The standard test to determine the hardness of metals is Brinell, Rockwell, and Vickers. The hardness is an important property for cutting tool materials and the metallic component which have to resist wear while working
Toughness may be defined as the property of the metal by which we can observe maximum energy before fracture takes place. It is measured by the amount of energy that a unit volume of material has after being stressed up to the point of fracture. Toughness decreases with an increase in temperature.
It is a very important property that is considered while selecting the material for a power press, punch, pneumatic, hammer, etc.
Stiffness is also known as the rigidity of metal. It may be defined as the property by which the metal will not deform or deflect when the load is applied. Although still stronger than cast iron, the latter is preferred for machine beds and frames because it is more rigid and less likely to deflect with consequent loss of alignment and accuracy.
Resilience may be defined as the property of metal by which it stores energy and resists shock and impact loads. It is measured by the amount of energy that can be stored per unit volume after being stressed up to the elastic limit. The material of higher resistance is used for spring.
The creep may be defined as the property of metal by which it deforms continuously and slowly under a steady load. Metal generally exhibits creep at Higher temperatures. The creep is considered an important property while designing the part of the IC engine and turbine blades as they are subjected to high pressure at high temperatures.
Electrical properties Of Metal
The characteristic of a metal that enables the flow of electric current through it is called electrical properties. The most important electrical properties of metals are conductivity, Resistivity, and dielectric strength
The conductivity may be defined as the electrical property of the metal which allows the flow of electric current. It is also defined as the reciprocal of resistance.
The metals such as copper and Aluminum are good electrical conductors. Since they are also highly ductile, they are used for making electrical transmission wires. Pure metals have good conductivity at room temperature. The material which is a bad conductor is called insulator.
Resistivity may be defined as the Electrical property of the metal by which it impedes or resists the flow of electric current. It is also defined as the reciprocal of conductivity. It increases linearly with an increase in temperature.
The insulating material will have the insulating ability up to a certain range of voltage. If the operating voltage is increased gradually, at some voltage it loses its insulating property.
The minimum voltage that can be applied to the insulating material which results in the destruction of the insulating properties of the material is defined as the dielectric strength. It is used in the selection of insulating materials.
Thermal Properties of Metal
The thermal properties of the metals are the characteristics of the metal which are influenced by the application of heat.
For example, when metals are heated, they observe the heat energy resulting in the change of dimension, the flow of heat from the higher temperature region to the load temperature region, liquefaction of metals from the solid state when temperatures are raised beyond the melting point, electrical conductivity, etc.
Thermal conductivity images the ability of the metal to transmit heat energy through it. The higher the thermal conductivity the greater the rate at which heat is conducted. Pure metals show only small changes in thermal conductivity with temperature. The thermal conductivity of Copper and Aluminum increases as the temperature decreases until a maximum is reached.
All metals and alloys to a greater or lesser extent, expand when heated and contract when cooled. The amount of expansion and contraction will be proportional to the change in temperature. Thermal expansion is characteristic of metals and alloys. This property of the metals will be useful in applications such as shrink-fit and bi-metal alloys.
The specific heat of a metal may be defined as the quantity of heat required to raise the temperature of a unit mass of a substance through 1 Degree Celsius.
The melting point is defined as the temperature at which it begins to melt when the heat is added to it.
Magnetic Properties of Metal
Magnetic properties of metal refer to the metal and alloys such as iron, and steel and associated alloying elements such as cobalt and Nickel. All other materials are non-magnetic. Metals and alloys are classified as either hard or soft. Hard magnetic materials retail magnetism after the initial magnetism has been removed.
Soft magnetic materials can be easily magnetized or demagnetized and they retain no magnetism when the magnetizing force is removed. Magnetic materials are used in a large variety of electrical and electronic components like computers, televisions, video cassettes, a transducer, etc.
Magnetic permeability is defined as a measure that indicates the ease with which magnetism may be developed in the materials. Hard magnetic materials have a low permeability Where are soft magnetic materials have a high permeability.
The coercive force is defined as the force which opposes the magnetizing force. It is applied to remove previous magnetization or residual magnetism. The Coercive force must be very small in magnetic materials.
Hysteresis is defined as when a ferromagnetic material is subjected to a gradually increasing magnetic field, simultaneously there will be a corresponding increase in the intensity of magnetization. When the field strength is decreased to zero. To reduce it to zero, a certain amount of magnetic field is applied in the reverse direction.
A similar phenomenon is observed even in the negative direction. The change in the intensity of magnetization always lags behind the change in the magnetic field strength. This phenomenon of magnetic materials is called hysteresis.
Chemical Properties of Metal
Some of the important chemical properties of metals considered in the selection of materials are corrosion, composition and acidity, and alkalinity.
All metals are extracted from their ores. A considerable amount of energy is spent during the extraction process. As a result, pure metals possess more energy compared to their ores. Metal will not be stable in its high-energy state. The two simple examples of corrosion result in iron and the formation of a green film on the surface of copper.
As a result, pure metals tend to revert to their natural state. When pure metals are exposed to the atmosphere of our environment containing liquid and gases, the surface of the metal starts deteriorating due to the chemical reaction. The Surface deterioration caused by the chemical reaction is called corrosion.
The properties of metal depend on the chemical composition of the elements present in the metals and alloys. By varying the proportion of the chemical composition the desired properties may be imparted.
Acidity and Alkalinity
Acidity is the Acid characteristics of the metals. Alkaline is the characteristic that neutralizes the acidity. Corrosion of steel is minimized by mentioning the boiler water alkaline.
What Are The 5 Properties Of Metals?
The five properties of metals are which are as follows
- Mechanical properties of metals
- Electrical properties
- Thermal properties
- Magnetic properties
- Chemical properties
What Are The Mechanical Properties Of Metal?
The mechanical properties of metal indicate the nature of its inherent behavior under the action of external force. It can be classified as follows
What Are The Thermal Properties Of Metal?
The thermal properties of the metals are the characteristics of the metal which are influenced by the application of heat which are as follows
- Melting Point
- Thermal Conductivity
- Thermal Expansion
- Specific Heat
In conclusion, metals are incredibly versatile and valuable in a wide array of industrial and technological applications. They possess an impressive set of physical and chemical properties that make them indispensable. When it comes to their mechanical attributes such as strength, ductility, and toughness, metals can be easily shaped and formed into different structures and components. Moreover, metals exhibit exceptional electrical and thermal conductivity, making them the ideal choice for applications that involve energy transfer, like electrical wiring and heat exchangers. Additionally, certain metals display magnetic properties, making them suitable for usage in electric motors and other magnetic devices.
Lastly, metals boast unique chemical properties that enable them to react with various elements and compounds, opening up a plethora of possibilities for their use in different chemical processes. When considering all these remarkable properties, it becomes evident that metals play a pivotal role in modern society as an indispensable material. Their importance will undoubtedly persist as we continue to advance technologically in the future.