Martensite Type FeCx ($x \le 0.06$) ($L2_{0}$) Structure : AB_tI4_139_b_a

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Prototype : CxFe
AFLOW prototype label : AB_tI4_139_b_a
Strukturbericht designation : $L2_{0}$
Pearson symbol : tI4
Space group number : 139
Space group symbol : $I4/mmm$
AFLOW prototype command : aflow --proto=AB_tI4_139_b_a
--params=
$a$,$c/a$


  • This should not be considered a true model of Martensite, a very complex material whose structure is sensitive to composition (Blackwell, 1996; Sherby, 2008). However, (Ewald, 1931) assign this the label $L'20, saying that this structure is $\alpha$–Fe with 6 atomic percent C. Although Ewald and Hermann present a long discussion of martensite (489, 576–583), they do not give this exact crystal structure, which we take from (Brandes, 1992) and (Pearson, 1967).
  • (Villars, 1995) and (Westbrook, 1995) ignore this structure and give the $L'2$ label to the ThH2 structure. We previously followed this notation, but in the interest of historical accuracy will relabel that structure with the name given to it by (Brandes, 1992) and (Pearson, 1967), $L'2_{b}$.
  • We should note that these last two references list the current structure simply as $L'2$.

Body-centered Tetragonal primitive vectors:

\[ \begin{array}{ccc} \mathbf{a}_1 & = & - \frac12 \, a \, \mathbf{\hat{x}} + \frac12 \, a \, \mathbf{\hat{y}} + \frac12 \, c \, \mathbf{\hat{z}} \\ \mathbf{a}_2 & = & ~ \frac12 \, a \, \mathbf{\hat{x}} - \frac12 \, a \, \mathbf{\hat{y}} + \frac12 \, c \, \mathbf{\hat{z}} \\ \mathbf{a}_3 & = & ~ \frac12 \, a \, \mathbf{\hat{x}} + \frac12 \, a \, \mathbf{\hat{y}} - \frac12 \, c \, \mathbf{\hat{z}} \\ \end{array} \]

Basis vectors:

\[ \begin{array}{ccccccc} & & \mbox{Lattice Coordinates} & & \mbox{Cartesian Coordinates} &\mbox{Wyckoff Position} & \mbox{Atom Type} \\ \mathbf{B}_{1} & = & 0 \, \mathbf{a}_{1} + 0 \, \mathbf{a}_{2} + 0 \, \mathbf{a}_{3} & = & 0 \, \mathbf{\hat{x}} + 0 \, \mathbf{\hat{y}} + 0 \, \mathbf{\hat{z}} & \left(2a\right) & \mbox{Fe} \\ \mathbf{B}_{2} & = & \frac{1}{2} \, \mathbf{a}_{1} + \frac{1}{2} \, \mathbf{a}_{2} & = & \frac{1}{2}c \, \mathbf{\hat{z}} & \left(2b\right) & \mbox{C} \\ \end{array} \]

References

  • E. A. Brandes and G. B. Brook, eds., Smithells Metals Reference Book (Butterworth Heinemann, 1992), chap. 6, 6–63, 7e edn.
  • R. Blackwell, Internal Friction Effects in Tempered Martensite, Nature 211, 733–734 (1966), doi:10.1038/211733a0.
  • O. D. Sherby, J. Wadsworth, D. R. Lesuer, and C. K. Syn, Revisiting the Structure of Martensite in Iron–Carbon Steels, Mater. Trans. 49, 2016–2027 (2008), doi:10.2320/matertrans.MRA2007338.
  • P. Villars and L. Calvert, Pearson's Handbook of Crystallographic Data for Intermetallic Phases (ASM International, Materials Park, OH, 1991), 2nd edn.
  • J. H. Westbrook and R. L. Fleischer, eds., Intermetallic Compounds – Principles and Practice (John Wiley \& Sons, Ltd., Chichester, England, 1995). Two Volumes.
  • W. B. Pearson, A Handbook of Lattice Spacings and Structures of Metals and Alloys, Volume 2, International Series of Monographs on Metal Physics and Physical Metallurgy, vol. 8 (Pergamon Press, Oxford, London, Edinburgh, New York, Toronto, Sydney, Paris, Braunschweig, 1967). N. R. C. No. 8752.

Found in

  • P. P. Ewald and C. Hermann, eds., Strukturbericht 1913–1928 (Akademische Verlagsgesellschaft M. B. H., Leipzig, 1931).

Geometry files


Prototype Generator

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