| Popis: |
The effect of the grain size of the filler on the mechanical properties (compressive, bending, and tensile strength and modulus of elasticity) of synthetic graphite is analyzed using data for commercial structural graphites. As the mean particle size of the filler (δav) decreases from 3000 to 1 μm, the modulus of elasticity increases, on the average, from 10 to 15 GPa, and the compressive, bending, and tensile strength increases by about one order of magnitude. The Griffith equation is used to evaluate the size of defects that initiate fracture (c c) in different types of graphites. It is shown that the factors determining the critical defect size depend on the particle size of the filler. For δav > 150 μm, c c is comparable to δav or δmax . In the range 30 < δav < 150 μm, c c is equal to or greater than δmax . In graphites with δav < 30 μm, c c far exceeds δmax and, presumably, corresponds to the particle size of the molding powder. |
