Abstract
From the point of view that fly ash has very fine particles which included silica and alumina component of ceramic material, composite materials using fly ash and aluminum powders were fabricated by spark plasma sintering technique. The bending strength showed the constant value of 530 MPa at the fly ash content lower than 9.1 %, however the strength decreased monotonically at the fly ash content higher than 9.1 %. In addition, the bending fracture strain decreased with increasing the fly ash content. From the fracture surface observation, the crack propagation was recognized as bypassing along interface of fly ash particle. This phenomenon indicated that the fly ash particles played a role for suppressing the crack propagation. By assuming fly ash particle as spherical shape, the Mises stress distributions were analyzed by finite element method. The high stress concentrated near interfaces of fly ash particles, because deformation degree of aluminum alloy matrix and fly ash were different. This result suggested that the cracks occurred around fly ash particle combined each other, because the agglomerated fly ash particles becomes large size when increasing the fly ash content. And the simulation results showed the agreement with experimental results of fracture strain on the bending test.
