Trapping of Sb by TaC and Cu precipitates in ion-implanted Fe

Experimental evidence is presented for trapping of Sb by TaC and Cu precipitates in Fe. These processes were studied during annealing at 873 K of Fe ion-implanted with either Ta, C, and Sb, or Cu and Sb. For both precipitates the derived binding enthalpy is ∼0.4 eV when referenced to an Sb solution site in the bcc-Fe phase. It is argued that this trapping occurs at the precipitate-host interface, and that it is due primarily to the associated structural discontinuity. In the Fe-Cu-Sb alloys, trapping was accompanied by two other processes which immobilize Sb, namely, dissolution into the fcc-Cu phase and formation of β-Cu3Sb. The trapping effects observed in these studies are of potential significance for the control of Sb embrittlement in ferritic steels.