Abstract
Internal friction phenomena of porous alumina were investigated to evaluate the damping capacity. Raw powder was formed into a rectangular parallelepiped by a uniaxial press, then cold isostaticaly pressed. The compacts were sintered by conventional sintering and capsule-free-Hot Isostatic Pressing (HIPing) at various temperatures between 1150 to 1500°C for 1h. Internal friction phenomena were evaluated by Q-1 obtained by resonance method. The value of Q-1 for conventional sintered samples were higher than that for HIPed ones at a given porosity and for a given Young's modulus. For the samples sintered at the same temperature, Q-1 showed a similar tendency. We reported previously that capsule-free-HIPing can enhance surface diffusivity by gas pressure. It is concluded that sintering process affects damping capacity on porous alumina, Young's modulus and damping capacity of porous alumina can be controlled independently by controlling the diffusion process.
