High damping functional materials prepared by spray deposition

High damping materials with good mechanical properties suppress undesirable mechanical vibration and wave propagation, and have wide application in no ise control and in the stability of vehicles and instruments. The effects o f alloying and extrusion on the damping behavior and mechanical properties of as-spray-deposited alloy ZA27 were investigated to develop a new functio nal material possessing high damping capacity and good mechanical propertie s. Three levels of cerium content, 0.3, 0.5 and 0.7 wt.%, were adopted to e valuate the effectiveness of modification. The damping capacities were meas ured at frequencies of 1 and 4 Hz over the 30-200 degreesC temperature rang e. At temperatures below 80 degreesC, the as-spray-deposited materials appe ar to have virtually no frequency dependency. Above 80 degreesC, the materi als become temperature sensitive, with the lower frequency exhibiting the h igher damping. The extruded, as-spray-deposited material has the highest da mping capacity and elongation values amongst all of them. The microstructur e of the as-spray-deposited high silicon alloy ZA27 modified by 0.5 wt.% ce rium was made up of fine lamella eutectoid, pores, light dot-like phases an d polygonal silicon-rich phases. The damping mechanisms are discussed in th e light of the data obtained from characterization of the microstructure an d the damping capacity. (C) 2000 Elsevier Science B.V. All rights reserved.