High damping functional materials prepared by spray deposition

Abstract

High damping materials with good mechanical properties suppress undesirable mechanical vibration and wave propagation, and have wide application in noise control and in the stability of vehicles and instruments. The effects of alloying and extrusion on the damping behavior and mechanical properties of as-spray-deposited alloy ZA27 were investigated to develop a new functional material possessing high damping capacity and good mechanical properties. Three levels of cerium content, 0.3, 0.5 and 0.7wt.%, were adopted to evaluate the effectiveness of modification. The damping capacities were measured at frequencies of 1 and 4Hz over the 30–200°C temperature range. At temperatures below 80°C, the as-spray-deposited materials appear to have virtually no frequency dependency. Above 80°C, the materials become temperature sensitive, with the lower frequency exhibiting the higher damping. The extruded, as-spray-deposited material has the highest damping capacity and elongation values amongst all of them. The microstructure of the as-spray-deposited high silicon alloy ZA27 modified by 0.5wt.% cerium was made up of fine lamella eutectoid, pores, light dot-like phases and polygonal silicon-rich phases. The damping mechanisms are discussed in the light of the data obtained from characterization of the microstructure and the damping capacity.