Properties of Metals

Contraction and Expansion

admin — Wed, 09 Sep 2009 09:14:55 +0000

When metals are heated of cooled, either contracts or expands. This is one of the properties of metals.

When metals are heated (at a high degree) it expands and becomes larger, while cooling metals causes it to contract or shrink in size. This is very important for metals that are used outdoors, to consider temperature changes and how it affects metals.

Fusibility

admin — Wed, 09 Sep 2009 09:04:21 +0000

Fusibility is a mechanical property of metals to be liquefied by heating.

This process is called welding, where metals are liquefied and joined together, when it hardens it becomes one piece. Steels liquefies at 2500°F, while aluminum alloys at 1,110°F.

Density

admin — Wed, 09 Sep 2009 08:42:50 +0000

Density is a physical and mechanical properties of metals which is defined as mass per unit volume.

Metals have higher density than non metals, this is because of the tightly packed crystals in the metal structure. Metal Density is a very important factor in structures, vehicles or machines as it requires balance, right weight etc.

Toughness

admin — Wed, 09 Sep 2009 08:09:01 +0000

Toughness (Mechanical Property of metal) is the ability of the metal not to break in pressures applied such as tearing, shearing, stretching, bending or deformity.

Toughness of a metal should be able to absorb the energy up to the fracture. Tough metals are desirable to vehicles, machines and structures.

Elasticity

admin — Wed, 09 Sep 2009 08:02:21 +0000

Elasticity is a Physical and Mechanical Property of metals to be able to return to its original shape after it has been deformed.

The amount of deformation is measured and is called strain. Every metal has an elastic limit, in which if it is exceeded then it would become a permanent deformity and cannot return to its original shape.

Ductility

admin — Wed, 09 Sep 2009 07:45:41 +0000

Ductility is a physical and mechanical property of metals that allows the metal to be deformed, drawn, bent or twisted into different shapes without fracture or breaking.

It is opposite to Brittleness and is somehow similar to malleability. Ductile metals are vital in creating wire or tubing because of its ease in forming while remaining in tact. Examples of Ductile metals are:

Platinum
Tungsten
Copper
Steel
etc.

Malleability

admin — Wed, 09 Sep 2009 07:29:17 +0000

Malleability is a physical and mechanical property of metals, which is the material’s ability to deform under stress without breaking or cracking.

Malleable metals are formed into thin sheets thru hammering, rolling or pressing. These sheets of metals are then used to form shapes for structural, vehicular or mechanical needs. Examples of Malleable metals are:

Copper
Gold
Magnesium
etc.

Brittleness

admin — Wed, 09 Sep 2009 07:14:09 +0000

Brittleness, a mechanical property of metals, is the property of a metals to bend or deform without breaking or shattering the metal.

The opposite of this is ductility which is the ability to deform without breaking or shattering the metal, while a brittle metal would break or crack without a change of shape. Examples of Brittle metals are:

Cast Iron
Cast Aluminum
Very Hard Steel
etc.

Brittle metals are not suitable for heavy loads, as it could break easily and can cause damages.

Hardness

admin — Wed, 09 Sep 2009 06:44:47 +0000

The mechanical properties of metals which is Hardness is the resistance to deformation, penetration, abrasion, cutting or distortion.

The hardness of metals can be measured using standard tests where a ball is pressed against the material and the size of the dent is the measurement. The different tests are:

Rockwell
Brinell
Vickers
etc.

Hardness of a metal can be adjusted by simply using different treatments such as the heat treatment and the cold working. Metals used in structures are formed from a soft state then heated to retain the finished shape.

Heat Conductor

admin — Mon, 07 Sep 2009 09:32:38 +0000

Heat Transfer or Conduction is the transfer of thermal energy because of temperature gradient between neighboring molecules.

Metals are known to be able to conduct heat and take it from a high temperature place to a lower temperature. A combination of vibrations of molecules as well as the free electrons makes the heat transfer.