Physical Properties Of Graphite Material

- Sep 09, 2017-

    The performance of graphite materials under the action of force is also known as mechanical properties. Graphite body deformation under the external force, if the deformation does not exceed the elastic limit, the external force after the removal of deformation can be restored, this performance is called elasticity, indicating that the parameters of graphite elasticity is proportional limit, elastic limit, elastic modulus, elastic flexibility, Poisson ratio and so on.Graphite Material
    (See the elasticity of graphite crystals, the elasticity of polycrystalline graphite) The deformation that cannot disappear after external discharge, called residual deformation. The ability of graphite to maintain residual deformation is called the plasticity of graphite, and the residual deformation is also called plastic deformation. The parameters of graphite plasticity are yield limit (flow limit), elongation rate, stress-strain relation, etc. The ability of graphite to resist external forces (see the stress-strain properties of polycrystalline graphite) is called the strength of graphite. The parameters of graphite strength are tensile strength, shear strength, flexural strength and compressive strength. (See the strength of polycrystalline graphite) the ability of graphite to resist crack propagation is called the fracture toughness of graphite, which indicates that the parameters of fracture toughness of graphite are critical stress intensity factor, crack propagation force, crack opening displacement and so on.Graphite Material
    (See graphite fracture toughness) the plastic deformation of graphite under certain stress increases with time, this process is called creep. The parameters of creep are characterized by creep stress exponent, creep time index and so on. (See graphite creep) under alternating stress, the energy loss in the graphite body is called internal friction. The parameters of internal friction are the internal friction peak, the half peak width of resonance curve and so on. (See carbon material and graphite material internal friction) The local resistance of graphite to external objects, called hardness, is the index of comparing the soft and hard graphite material. Because of the different testing methods, there are different hardness indicators. For graphite materials, the total can be divided into hardness and rebound hardness of two categories.Graphite Material
    The mechanical meaning of various hardness is different from each other, but can be compared by experiment. The hardness is calculated by a certain load, the specified shape and size of the special pressure head, pressure into the tested parts, the surface of the specimen to the size of local plastic deformation, to calculate the hardness of the specimen. As the pressure head, load and pressure into the duration of the different, pressure into a variety of hardness, such as Brinell hardness, Rockwell hardness, Nup hardness, Vickers hardness and so on. (See hardness test method) rebound hardness is a special ball or small hammer from a certain height of free fall, the impact is tested and the size of the hardness is characterized by the amount of strain energy stored in the impact of the specimen, and the size of the strain energy is determined by the height of the small hammer bounce.Graphite Material