Mechanical spectroscopy study of thermo-mechanically treated 51CrV4 steel

The CrV-alloyed heat-treatable steel (51CrV4) used for shafts is studied with respect to the influence of different heat treatment and deformation regimes on amplitude (strain amplitude 10−6–10−3) and temperature dependent (293–800 K; 1–600 Hz) damping. Specimens with different metallographic constituents were measured with and without magnetic field to distinguish between dislocation and magnetoelastic damping. Coercivity of all samples as well as microhardness increases in the order: ferrite–pearlite, as received, bainite and martensite. A clear difference in temperature and amplitude dependent internal friction was detected, too. A Snoek-Köster peak was found to be highest in martensitic state correlating with the dislocation density and reversible relaxation strength. Reversible stress relaxation measurements performed at room temperature from 3 s to 1 h and at a strain of 2 × 10−5 led to a reversible relaxation strength of 0.001 for all mentioned metallographic constituents except the martensitic one which was observed to be about four times higher.