Effect of Titanium on the Behavior of Carbon in α-iron

Abstract

Internal friction and strain aging were studied in carburized Fe-0.5 at %Ti alloys. The carburized specimens were heated at 720°C in herium of 1atm and quenched. The Snoek damping was found to occur by the same single relaxation process as that of Fe-C alloy system, and the influence of texture, grain boundaries, cementite and magneto-mechanical damping on the relaxation strength were discussed. Strain aging was done at 15°C for 2 minutes under the unloaded and loaded condition.
The change of the height of Snoek damping (Q^-1max) and the stress increment by Snoek ordering (ΔY) with carbon content in the alloy were distinguished into three regions and discussed.
It was found that in the region from zero to 0.12 wt% carbon and ΔY were zero, this indicating that titanium strongly binds carbon, from 0.12 to 0.15 wt% carbon Q-1max and ΔY in- creased linearly with carbon concentration, which suggests that carbon dissolves into crystal lattice, and exceeding 0.15 wt% of carbon Q^-1max and ΔY decreased with carbon content, which illustrates that cementite precipitation occurs.
It was concluded that titanium atom and carbon atom combined by the atomic ratio of 1 to 1 and that the solubility of carbon increased by 7.5 times due to the addition of 0.5 at %Ti at 720°C.