Martensite Type
FeC$_{x}$ ($x < 0.06$) ($L'2_{0}$) Structure: AB_tI4_139_a_b-002
| Prototype | C$_{x}$Fe |
| AFLOW prototype label | AB_tI4_139_a_b-002 |
| Strukturbericht designation | $L'2_{0}$ |
| ICSD | none |
| Pearson symbol | tI4 |
| Space group number | 139 |
| Space group symbol | $I4/mmm$ |
| AFLOW prototype command |
aflow --proto=AB_tI4_139_a_b-002
--params=$a, \allowbreak c/a$ |
Other compounds with this structure
FeN$_{x}$
- 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 $L'2_{0}$, saying that this structure is
$\alpha$–Fe with 6 atomic percent C.
Although (Ewald, 1931) 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 ThH$_{2}$ 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 $L'2$.
- $L'2_{0}$ FeC$_{x}$ and $\beta$–LiFeO$_{2}$ have the same AFLOW prototype label, AB_tI4_139_a_b. They are generated by the same symmetry operations with different sets of parameters (
--params) specified in their corresponding CIF files.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&- \frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}a \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{1}{2}a \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}a \,\mathbf{\hat{y}}- \frac{1}{2}c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $0$ | = | $0$ | (2a) | C I |
| $\mathbf{B_{2}}$ | = | $\frac{1}{2} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{2}$ | = | $\frac{1}{2}c \,\mathbf{\hat{z}}$ | (2b) | Fe I |
References
- E. A. Brandes and G. B. Brook, eds., Smithells Metals Reference Book (Butterworth Heinemann, 1992), chap. 6, pp. 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).
- 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).
Found in
- P. P. Ewald and C. Hermann, eds., Strukturbericht 1913-1928 (Akademische Verlagsgesellschaft M. B. H., Leipzig, 1931).
Prototype Generator
aflow --proto=AB_tI4_139_a_b --params=$a,c/a$