![]() Shine or sheen - usually silver in colour (some are gold or reddish).Įxamples of metals include:- copper, aluminium, steels (mild steel, stainless steel, high and medium carbon steel, mild steel), silver, gold, zinc. They can also have sharp edges, ring when struck and have a metallic To their mechanical and physical properties - density/heavy, cold/thermalĬonductivity, hard/impact resistance etc. These properties determine how you you interact The unit of density is theĭo your senses tell you. Self finishing materials need no further treatment other than cleaningĭensity is mass per unit volume. light passes through but may be refracted. ![]() Opacity light cannot pass throughĮasily, translucency - light passes through but is diffuse, translucency Especially important for metals and polymersĪ measure of light transmission. The abilty to change easily into a molten state when heated (withoutĬhemical breakdown/burning). To enhance materials appearance and corrosion resistance. A range of coatings and surface finishes are used Is resistant to the effects of UV light which would quickly cause normal Plastics haveīeen developed or mofified to withstand hostile environments e.g. The ability to withstand environmental attack and decay. Ferrous metals are generallyĪble to be attracted by a magnet. Some metals can be magnetised (most steels). Has a value of 17 x 10 to the power of minus 9 while polythene has Very low values areĬonductors and high values are insulators. Tables of data usually show the resistivity of materials. metals and graphite are good conductors.ĭo not conduct electricity - plastics (polymers), rubber (elastomers) How well the material conducts electricity Poor conductors are called insulators - clearly this will often be Has a value of 35 and rubber which is an insulator has a value of 0.15. So copper which is a good conductor has a value of 283 whereas lead Unitįor thermal conductivity are Watts per metre Kelvin - W/mK Most metals are good conductors of heat, especially copper and aluminium. The ability to withstand wear and tear throughĪ general property of resistance to changes in shape or size. The unit for tensile strength is the MNĪ general property. Good examples are gold, copper, titanium, wrought iron, low carbon steels The ability to be drawn out into a thin wire or threads. Into a thin sheet is the literal meaning. Rolling or by any other method of applying pressure. The ability to plastically deform and shape a material by forging, The ability of a material to return to its original form after a load The materials which deform permanently when small forces are applied ![]() ![]() OppositeĪ material that absorbs impact (sudden forces or shocks such as hammerīlows) well is tough - this is the opposite to brittleness. ![]() Good examples are Cast iron, concrete, high carbonĬeramics, and some polymers such as urea formaldehyde (UF). This method is less accurate.Ī material that has a tendency to break easily or suddenly withoutĪny extension first. The reading is taken directly using a dial. The indent -the VHN is also used for comparisons.Ī ball for softer materials and a pyramid cone for hard materials. Uses a diamond square based pyramid - a microscope is needed to Hardness number HB which can be used to compare The methods used for testing hardnessĪre the Brinell test which uses a hardened steel ball and produces Well known hard materials include diamond and hardened high carbon Means they have a low resistance to impact. Hardness is a measure of how easily a material can be scratched The general ability of a material to withstand an applied force. ![]()
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