Damping Characteristics of Fe-C-Sn-Pb System Infiltrated Alloys
1989 Volume 36 Issue 8 Pages 933-938
Details
1989 Volume 36 Issue 8 Pages 933-938
Damping characteristics of sintered Fe-0.030 mass%C and Fe-0.014%C-2%Sn compacts which were infiltrated with pure Pb or Pb-2%Sn were investigated by using the magnetic driving resonant vibrating method. The purpose of C and Sn additions to Fe base skeletons was in improving the strengthening of skeletons, and Sn addition to Pb was in improving the wettability of infiltrants to Fe base skeletons. Infiltrated compacts were produced by sintering at 1273 K for 7.2 ks and then infiltrating at 1123 K for 600 s in purified H2 atmosphere.
Results obtained were summarized as follows:
(1) The ratio of infiltration (volume of infiltrants/total volume of porosity in the skeleton) for Fe-C-2%Sn compacts was a little inferior to that for Fe-C compacts, because of the formation of closed pores by melting out of Sn.
(2) Typical Snoek peaks were observed for Fe-0.030%C/Pb (A/B: A; skeleton, B; infiltrant) and for Fe- 0.030%C/Pb-2%Sn compacts in the temperature dependent internal friction (Q-1) curves. Sn addition to Fe base skeletons markedly enhanced the value of Q-1 at the temperature of the appearance of Snoek peak, o.iginating in the relaxation of grain boundary diffusion of Sn. Sn addition to Pb infiltrant generally tended to lower the value of Q-1.
(3) Q-1 for Fe-0.030%C/Pb or /Pb-2%Sn at 433 K appearing Snoek peak did not show the strain amplitude dependency up to εmax=5-8×10-8, and over that, increased with the increase of εmax- On the other hand, Q-1 for Fe-0.014%C-2%Sn/Pb or /Pb-2%Sn did not show the strain amplitude dependency up to smax??1×10-5. Q-1 of all specimens described above at room temperature showed the strain amplitude dependency above εmax??1×10-5.
(4) Damping index of Fe-0.030%C/Pb or /Pb-2%Sn was about 9%, rather higher than that of Fe-0.014%C-2%Sn/Pb or /Pb-2%Sn. On the other hand, mechanical properties such as tensile strength and hardness of Fe-0.014%C-2%Sn/Pb or /Pb-2%Sn was inversely a little higher than that of Fe-0.030%C/Pb or /Pb-2%Sn.
