Carbon Fiber Properties.
Carbon fiber’ also called sometimes as ‘Graphite fiber’. In today’s era manufactures are looking for material that has more strength and is lighter in weight to achieve greater safety and efficiency.
Carbon-fiber-composites are the solution to these manufacturer’s requirements. Carbon-fiber’s have not only the highest compressive strength properties of all the reinforcing materials, but at the same time, it has a low coefficient of thermal expansion. and also high strength to weight ratio.
As compared to steel which is mainly used in manufacturing, carbon fibers have lower density and more strength. Its density is very less as compared to Steel and other metals used in manufacturing. They are is composed of mostly carbon atoms that are in the form of several thousand long, thin strands of material.
‘Carbon Fiber’ Special Properties:
• Lower in Weight and Density
Carbon fiber composites have lower mass and density as compared to other metals. It has a density of 1.6 g/ cm3 whereas other metals such as aluminum are 2.7g/cm3 and steels density is 8 g/cm3.
Hence if we compare the weight of other metals such as steel which weights 8kg for 1mmx 1mx1m sheet, aluminum weighs around 2.7kg. On the other hand, these fiber panel weighs only 1.6kg, which compared is 5 times lower than the steel’s weight.
Hence, the major weight to strength advantage makes it the first choice in Precision Machines. Machines such as Formula 1 cars, Racing Bikes, Robotic arms Gripping parts, Aircraft, Spaceships and many more are such examples.
• Electrical Conductivity is high
There are both, advantages and disadvantages of this property of Carbon-fibers. In Industries such as Shipbuilding due to this property at most care has to be taken off while installation; as Carbon-fibers conductivity can facilitate galvanic corrosion in the fittings.
• It has Resistant to Corrosion and are Stable Chemically.
By Itself, These fibers do not deteriorate. But other matrices such as Epoxy are sensitive to sunlight and need to be protected. Any other matrices might also be reactive.
• They have Resistance to Fire.
If we compare with existing materials that are very difficult to use in producing fire-resistant clothes. Carbon-fiber can be the best solution as they are very delicate and can be used in defensive clothes for firefighting. Such a very good example is a Nickel covered fiber.
Since carbon fiber is otherwise artificially inactive, it very well may be utilized where there is fire joined with destructive substances.
• The Tensile Strength of Carbon-Fiber is very good.
Tensile strength or ultimate strength is the maximum stress that any material can withstand while in tension or pull before necking or breaking. Due to Internal flaws, Brittle materials such as carbon fibers do not always fail at the same stress level but, tend to fail at minimal strains.
Testing involves taking a sample with a fixed cross-section area and then pulling it gradually by increasing the force until the sample changes shape or break. These Fibers, being only 1/200th of an mm in diameter, are made into composites of appropriate shapes.
• Specific strength: These Fibers are known for High Strength to Weight Ratio.
Strength to weight ratio- as to suggest is measured by how strong and lightweight the material is. The strength of a material is the force per unit area at failure, divided by its density. Any material that is strong and also light in weight has a favorable Strength/weight ratio.
The specific strength of Carbon-fiber is very high. It is 5 times lighter than steel and has more strength than Steel.
• Rigidity: It is a very rigid material.
Young Modulus is used to find out the Rigidity or stiffness of any material. This is tested by how much the material deflects under the stress applied. As per the lab tests it is found that Carbon-fiber reinforced polymer is twenty(20x) times stiffer than pine and 2.5 times stiffer than Aluminum and double stiffer than Glass reinforced plastic or polymers.
• It has good resistance properties to Fatigue.
Carbon-Fiber Composites have very good resistance to fatigue property. Carbon-fibers are superior to E glass fibers in fatigue, static strength as well as in stiffness. When carbon fiber fails it usually fails catastrophically.
Damage in tensile fatigue can be seen due to a reduction in its stiffness, with numbers of stress cycles in large numbers (unless the temperature is high). It is also seen that failure is unlikely to be a problem when cyclic stresses coincide with the fiber orientation.
• These fibers are X-Ray Permeable, Biologically inert, and Non-Poisonous.
These properties of Carbon fiber make it very useful in Medical applications. Carbon-fibers use in Prosthesis parts, tendon repair and implants, surgical instruments and x-ray Machines are in making and Researched. Though carbon fibers are not poisonous, they can be quite irritating and it’s long term exposure which is unprotected needs to be limited. The matrix either with epoxy or polyester can, however, be toxic or proper care is required.
• Properties of Thermal Conductivity.
Under steady conditions, Thermal conductivity is the amount of the heat transferred through a unit of thickness, in the normal direction of a surface of unit area. Due to the gradual increase in temperature. In other words, it’s measured by how easily heat flows through a material.
As there are many combinations on the design of carbon fiber, it is not possible to point out the exact thermal conductivity. Special types of Carbon Fiber are specially designed for high or low thermal conductivity.
• They are a Low Coefficient of Thermal Expansion.
The coefficient of expansion is a measure of how much a material expands and contracts when the temperature changes low or high. In a sufficiently high mast contrasts in Coefficients of thermal expansion of different materials can marginally adjust the apparatus pressures.
It is suitable for applications wherein case if small motions or movements are critical, due to its Low Coefficient of Thermal Expansion. Telescopes and other optical machinery are other such applications.
• Are Relatively Expensive.
Carbon-fibers have all the advantages such as strength, Rigidity, Lighter in Weight, but one of the disadvantages for its popularity in use is its cost. Buy, as Specific Strength is critically important in applications such as Spaceships, Aircraft, Racing cars and Bikes to name a few, it is worth an extra cost. Also, they are low in maintenance and are an added advantage of the materials used.
• These Fibers are brittle in Nature.
In case if the fibers bend, they have a property of failure at a minimal strain. Layers in carbon fibers are formed by strong covalent bonds. Its Sheet-like gathering allows the proliferation of cracks.
Applications of Carbon-Fiber Composites in Industrial Products