Effects of hot extrusion on damping capacity of spray deposited ZA27-4%Si alloy

ZA27 alloy doped with 4% Si (named ZA27-4%Si ) was prepared by spray deposition technique, and then the alloy was hot extruded at 250°C. The damping behaviors of the alloy un-extruded and un-extruded were investigated using a multifunction internal friction apparatus. The experimental results show that the damping capacities of the alloy increase with decrease of vibrate frequency and increase of temperature, whereas vibration amplitude has no effect on the damping capacities of the alloy. Hot extrusion can improve damping capacity of the spray deposited ZA27-4%Si alloy above 50°C. For example, the damping capacity of the extruded spray deposited ZA27-4% Si alloy is 5.07 × 10^-2 at 1 Hz and 105°C, which is higher 20% than that of the alloy un-extruded. The damping behaviors of the alloy can be explained with interface damping and dislocation damping mechanism.