The strain amplitude dependent internal friction at room temperature and the transition
temperatures of CuAlMn-shape memory alloys with Al contents from 8.9 wt.% to 12.7 wt.% and Mn
contents from 4.7 wt.% to 9.3 wt.% were investigated. The investigated strain range was 10-6 – 10-3.
Rods of various compositions were die cast and machined to single clamped damping bars. Their
transition temperatures and amplitude dependent damping was determined in as cast and homogenized
state. The damping in the investigated shape memory alloys was found to be generally much higher
than in metals without martensitic transition. In as cast state some alloys exceeded the damping of a
Sonoston type alloy measured in comparison for strains higher than 3 x 10-5. The influence of grain size
on damping was investigated by additional sand casting and the use of Boron for grain refinement. It
was found that only the material with the biggest grains had a noticeable higher damping over the
whole measured strain range. Homogenization heat treatment can still extremely increase the damping
of CuAlMn alloys. After homogenization this extremely high damping decreases slowly to medium
values in the order of as cast alloys.