Physical properties are significant in identifying one material from another. Physical characteristics are frequently considered to be a broader category than mechanical qualities in the study and application of metallurgy, however not all physical properties are interchangeable. The method of testing is the most effective way of distinguishing physical properties from mechanical properties in most cases. In contrast to mechanical qualities, which must be measured by applying forces to the material, physical attributes can be assessed without affecting the material itself. Nevertheless, physical attributes do alter depending on the context in which they are found. For example, due to the laws of thermal expansion and contraction, most metals have a larger density at lower temperatures than at higher temperatures. Colour and appearance are both physical attributes. Metals have a variety of physical properties, including:
1. Corrosion resistance is an
2. Density
3. Melting point
4. Thermal
5. Capacity for generating heat
6. Thermoelectric conductivity
7. Thermal expansion is the seventh factor to consider.
8. Electrical conductivity is a measure of how well a device conducts electricity.
9. Magnetic characteristics are important.
The melting points of metals are significant for a variety of industrial applications. When tungsten is heated to exceptionally high temperatures (3,370°C), it fuses or melts, whereas caesium is heated to a temperature of 28.5°C. Silver is the best metallic conductor of electricity among all metals. Copper, gold, and aluminium are the next metals to be discovered in the sequence listed. Almost all metals are relatively strong heat conductors, with silver being the most conductive. Copper and aluminium are also particularly conducive. The radioactive metal uranium is used in reactor piles to generate steam and electricity, and it is also used in nuclear power plants. Plutonium is another radioactive element that is utilised in nuclear weapons, nuclear reactors, and pacemakers, among other applications. Some of the radioactive metals that are not present in nature, such as fermium and seaborgium, are created by nuclear bombardment and are hence radioactive. Some elements, such as arsenic and antimony, have properties that are both metallic and nonmetallic, and as a result, they are referred to as metalloids. Furthermore, although all metals crystallise, this is also true of certain nonmetals, such as carbon and sulphur, which are examples of such elements.
CORROSION RESISTANCE, DENSITY AND MELTING POINT
Corrosion resistance
It is the ability of a substance to resist a chemical reaction and progress toward a more stable state in its surroundings. Aluminium, silicon, titanium, and their alloys are naturally corrosion resistant due to the formation of an unreactive layer on their surfaces as soon as they are exposed to air. Stainless steel is a typical alloy used in a wide range of applications that require corrosion resistance. Stainless steel alloys, in contrast to carbon steel, are capable of withstanding surface corrosion when exposed to conditions that would ordinarily promote corrosion, such as moist, acidic, or high temperatures.
Density
The density of an object can be calculated using a straightforward formula: the object’s mass (M) divided by the volume (V). Initially, the practical application of density was to detect the validity of gold, as in the myth of the golden crown, which is still popular today. Gold is a great choice for density testing because it is a significantly denser material than other metals, having an average density of 1,206 lbs. per cubic foot, making it an excellent candidate for density testing. Alloys with lower density are more typically found in the manufacturing industry. Steel weighs around 494 pounds. per cubic foot, while stainless steel weighs somewhat less. Titanium has a density of approximately half that of steel, whereas aluminium has a density of approximately one-third that of steel. In practice, this means that a steel component will weigh approximately three times as much as an aluminium component of the same size and shape. Steel, on the other hand, has other advantages such as hardness and strength, which means that smaller volumes or thinner layers of material can deliver the same or higher performance when compared to other materials.
Melting Point
In the presence of atmospheric pressure, the melting point of a material is defined as the temperature at which it transitions from a solid to a liquid state. The melting point of an alloy can be an important aspect in determining whether or not it will be suitable for a given application. Varied alloys have different melting point ranges, which are defined by the elements that make up their chemical composition. For example, an alloy containing a high percentage of tin or aluminium will melt at a significantly lower temperature than an alloy containing a high amount of iron or nickel alone.
THERMAL CHARACTERISTICS
Heat capacity, thermal conductivity, and thermal expansion are some of the thermal qualities that can be measured. In the industrial industry, all three qualities are key considerations for selecting the appropriate alloy.
1. Heat capacity, also known as specific heat, is the amount of energy required to change the temperature of a material. It is a critical factor in estimating casting solidification because it is a crucial component of the process.
2. Heat conductivity (also known as thermal conductivity) is defined as the rate at which heat can be carried through a substance, and one characteristic that all metals share is high thermal conductivity. Electrical conductivity is a separate property from thermal conductivity, but it has a proportional relationship with it. Metals such as copper and gold, which are well-known for their electrical conductivity, are also excellent heat conductors. Copper and gold are particularly good thermal conductors.
3. Metals expand when heated and contract when cooled, and thermal expansion is a term that describes this phenomenon. When creating tooling for metal casting, this characteristic is very crucial to consider. In order to account for shrinkage during the cooling process, patterns and moulds must be larger than the final product.
MAGNETIC PROPERTIES
The way a material responds to an applied external magnetic field is referred to as its magnetic characteristics (or magnetism). Diamagnetic, paramagnetic, ferromagnetic, antiferromagnetic, and ferrimagnetic magnetic responses are all possible classifications for this magnetic reaction.
1. Diamagnetic – repelled by magnetic fields
2. Paramagnetic – displays a lack of magnetic order.
3. Ferromagnetic – the most powerful form of magnetism.
4. Antiferromagnetic – may exist at sufficiently low temperatures, but vanishes at/above Néel temperature
5. Ferrimagnetic – a weak kind of ferromagnetism that exists in nature.
Iron is one of the strongest magnetic metals, and as a result, ferrous metals (metals containing iron) such as steel display varying degrees of magnetism—specifically, ferromagnetism—to varying degrees.
CONCLUSION
There are so many differences between metals and nonmetals in terms of hardness, ductility (the capacity to be formed into wire), malleability, tensile strength, density, and melting temperature that it is impossible to make a clear demarcation between them and the other elements. The hardest elemental metal is chromium, while the softest is caesium, with chromium being the hardest. Copper, gold, platinum, and silver are among the most ductile metals. The majority of metals are malleable, with the exception of gold, silver, copper, tin, and aluminium, which are particularly malleable. Copper, iron, and platinum are just a few of the metals that have high tensile strengths. During normal temperatures, the densities of three metals (lithium, potassium, and sodium) are less than one gram per cubic centimetre, making them denser than water and consequently lighter than water. Heavy metals include osmium, iridium, platinum, gold, tungsten, uranium, tantalum, mercury, hafnium, lead, and silver, and they are listed in order of density from most dense to least dense.