Experimental measurements of the correlation factor for solute diffusion
Final Report Abstract
The original goal of the project – the first experimental measurements of the tracer correlation factor – is closely approached and an estimate is provided for Cd diffusion in the Pd3Gd alloy. At the moment the tracer diffusion and PAC measurements are not performed at the same temperature that will avoid the uncertainties related to an extrapolation of the measured temperature dependencies. However, we are sure that our cooperation partner, Prof. Gary Collins (WSU) will extend his measurements down to about 730°C, a temperature for which reliable tracer data could be produced using natural Cd and SIMS profiling. In total, we are considering the project as a success (in spite of a number of encountered difficulties): A method of temperature calibration, which utilize Ni diffusion measurements with highly enriched 64Ni isotope and SIMS profiling, is elaborated and applied for cross-checking the furnaces used for the tracer measurements and for perturbed angular correlation analysis. - For the first time a correlation factor for solute tracer diffusion is measured for Cd diffusion in the L12 ordered Pd3Gd. A value of about 0.0007 is experimentally found at 600°C and it agrees generally with the predictions for Cd diffusion in a similar system, the L12 Ni3Al alloy. - A novel approach for a rigorous determination of the concentration-dependent tracer diffusion coefficients using a tracer-interdiffusion couple technique is elaborated. The method is verified for disordered Fe-Ga and B2 ordered NiAl-based alloys. - It is shown that the changes of molar volume have a minor impact on the derived tracer diffusion coefficients. - The developed approach demonstrated an immense potential for producing highly accurate mobility databases in multicomponent alloys. In fact, the concentration-dependent tracer diffusion coefficients can reliably and rigorously be measured along a single (and arbitrary) composition profile, which has being developed in the given diffusion couple. Simultaneously, there is no need for determination of the matrix of interdiffusion coefficients, the problem which still has no analytical solution for interdiffusion in alloys with the number of components exceeding three. - The impact of jump correlations on diffusion in Pt-modified NiAl alloys is explained, that is important for technological applications of such materials as bond coats for Ni-based superalloys.
Publications
-
On the Analysis of Composition Profiles in Binary Single-Phase Diffusion Couples: Systems with a Strong Compositional Dependence of the Interdiffusion Coefficient, Defect Diffusion Forum 383 (2018) 23-30
B. Tas Kavakbasi, I.S. Golovin, A. Paul, S.V. Divinski
-
Atomic transport in B2-ordered Al(Fe,Ni) alloys: Tracer-interdiffusion couple approach, Intermetallics 126 (2020) 106920
G. M. Muralikrishna, V.A. Esin, K.N. Kulkarni, B.S. Murty, G. Wilde, S.V. Divinski
-
Composition dependence of Fe tracer diffusion coefficients in Fe–Ga alloys: a case study by a tracer-interdiffusion couple method, Acta Materialia (2020)
G.M. Muralikrishna, B. Tas, N. Esakkiraja, V. Esin, K.C. Hari Kumar, I.S. Golovin, I.V. Belova, G.E. Murch, A. Paul, and S.V. Divinski
-
Diffusion, defects and understanding the growth of multicomponent interdiffusion zone between Ptmodified B2 NiAl bond coat and single crystal superalloy, Acta Materialia 195 (2020) 35- 49
N. Esakkiraja, A. Gupta, V. Jayaram, T. Hickel, S.V. Divinski, A. Paul
-
Novel Multicomponent B2 Ordered Aluminides: Compositional Design, Synthesis, Characterization and Thermal Stability, Metals 10 (2020) 1411
G.M. Muralikrishna, A.C.M. Esther, K. Guruvidyathri, Ph. Watermeyer, Ch.H. Liebscher, K.N. Kulkarni, G. Wilde, S.V. Divinski, and B.S. Murty
-
Tracer diffusion in multi component pseudo-binary B2 aluminides, Scripta Materialia 178 (2020) 227-231
G. M. Muralikrishna, M. Vaidya, B.S. Murty, S.V. Divinski, G. Wilde
