Auger analysis of fracture surfaces of temper embrittled 2.25 Cr-1Mo steel containing rare earth additions
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Auger Analysis of Fracture Surfaces of Temper Embrittled 2.25 Cr-lMo Steel Containing Rare Earth Additions
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M.J. GRAHAM, G. I. SPROULE, and P. HO
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Fig. 3--Thickening kinetics of Pd2Si.
Stark ~~has also determined that parabolic (time to the onehalf power) reaction kinetics are a characteristic of grain boundary diffusion based film thickening as well as the well-known lattice based process. Thus, the isotope separation and growth kinetics are consistent with either process. The major finding of this research is, therefore, that isotope separation does occur during thin film growth. As a consequence, the measured separation of the isotopes of a species in a thin film reaction yields information about the mobile species just as is found in marker movement studies. It is clear that no isotope separation of the silicon would have appeared if that element had not participated in the reaction. In addition, further information may be deduced about the mechanism of film growth from the slope of the isotope concentration ratio following Stark's analysis. Sputter deposited layers of Pd on (111) Si were annealed at 300 ~ X-rayed to demonstrate the formation of Pd2Si; AES determined the silicide-reactant interface location; and SIMS data on Si yielded isotope separation. In the latter, the lighter silicon isotope was found at higher concentrations farther from the silicon source.
This research was supported in part by the Metallurgy Division of the National Science Foundation. REFERENCES 1. R.W. Bower, P. Siguard, and R. E. Scott: Solid St. Electron, 1973, vol. 16, pp. 1461-63. 2. G.A. Hutchins and A. Shepela: Thin Solid Film, 1973, vol. 18, pp. 343-45. 3. W.D. Buckley and S.C. Moss: Solid St. Electron, 1972, vol. 15, pp. 1331-33. 4. C.J. Kircher: Solid St. Electron, 1970, vol. 14, pp. 507-08. 5. D. Siguard, R.W. Bower, W.F. Von der Weg, and J.M. Mayer: Thin Solid Film, 1973, vol. 19, pp. 319-22. 6. S.S. Lau and D. Siguard: J. Electrochem. Soc., 1974, vol. 121, pp. 1538-40. 7. W.K. Chu, S.S. Lau, J.W. Mayer, H. Muler, and K.N. Tu: Thin Solid Film,.1975, vol. 25, pp. 383-85. 8. J.M. Poate, K.N. Tu, and J.W. Mayer, eds.: Thin Film, Interdiffusion and Reactions, Wiley-Interscience, New York, NY, 1978. 9. J.P. Stark: Acta Met., in press. 10. J.P. Stark: Acta Met., in press.
2558--VOLUME 14A, DECEMBER 1983
Metalloid impurities such as P have a deleterious effect on the mechanical properties of steels when they segregate to grain boundaries. The temper embrittlement of 2.25 CrIMo steel is considered to be promoted by the segregation of P (together with other impurities) to prior austenite grain boundaries (e.g., References 1 to 3). Seah et al. 4 have reported that the temper embrittlement of P-containing low alloy steels can be reduced by the addition of rare earth elements such as La, and recent impact tests have supported this view. s'6 In this study we have examined fracture surfaces of a temper embrittled steel containing Ce and La
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