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Effect of Fe addition on ordering kinetics in Ni3Al1-xFex . Monte Carlo simulation

Rafal Kozubski ,  Ewa Partyka 

Jagiellonian University, Institute of Physics (IF UJ), Reymonta 4, Kraków 30-059, Poland

Abstract

Experimental studies of the effect of Fe alloying on the long-range ordering kinetics in Ni3Al1-xFex revealed a decrease of the activation energy for "order-order" relaxations with an increase of Fe concentration. For low Fe concentrations the activation energy was close to the one measured for Fe* tracer duffusion in Ni3Al.

The effect has now been modeled in atomistic scale by means of Monte Carlo simulations of a quasi-binary L12-ordered system A3B1-xCx with an Ising-type Hamiltonian. "Order-order" kinetics were simulated within Glauber dynamics implemented with vacancy mechanism of atomic jumps. The reality of Ni3All-xFex has been simulated by evaluating the atomic interaction energies in the way that the stability of L12 superstructure gradually decreases when the C concentration x increaes. The multi-time scale character of the relaxations known from the case of Ni3Al was again observed. Detailed analysis of atomic jump statistics revealed: (i) a dominance of the C-atom jumps in the creation/elimination of antisite defects; (ii) an increased vacancy availability in the 1st co-ordination shell of the C-atoms with respect to the A- and B-atoms. The results elucidate the role of Fe alloying in the kinetics of chemical ordering in Ni3Al.

 

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Related papers

Presentation: Oral at E-MRS Fall Meeting 2006, Symposium H, by Rafal Kozubski
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-11 17:13
Revised:   2009-06-07 00:44