徐祖耀文选(续)

　　承袭前集《徐祖耀文选》，《徐祖耀文选（续）》这本书系统精选徐祖耀近10年来在材料科学领域发表的68篇英文学术论文，集中反映其在马氏体与贝氏体相变、超高强度结构钢、纳米材料的结构稳定性与相变机制、形状记忆材料等方面的进一步探索及创新性成果，以为同仁提供宝贵的借鉴。

　　《徐祖耀文选（续）》可供从事材料科学、金属学、固体物理、机械等方向的研究人员及相关专业的高校师生参考。

Foreword
序
1 Martensitic and bainitic transformations
2 Ultrahigh strength steels and related Microstructural
Contron
3 Structual Stability and Phase Transformation in Nano-Sized
Materials
4 Shape Memory Materials and Shape Memory Effect
5 Characterization of Microstructure Related to Magnetic
Property
6 Appendix

　　1.Introduction
　　It is well known that theγ→ε transformation in Fe-Mn-Si based
shape memory alloys is associated with stacking faults (SF)， while
the stacking fault tetrahedron(SFT) plays an important role in the
SF initiation [1，2].The stacking faults have been extensively
investigated on various aspects， such as the thermodynamic
calculation of SF energy [3，4]， the XRD measurement of SF
probability (Psf) [5] and the CTEM and HRTEM observations of SF and
SFT [6，7]. However， only little work was done on their symmetry
characteristics till now. On the other hand， their momechanical
training as an effective method to improve the shape memory effect
(SME) may lead to formation of transition phases of which some have
been examined by internal friction experiment in
Fe-26.4Mn-6.0Si-5.2Cralloy [8] and characterized by TEM in
Fe-30Mn-6Si alloy [9]， but the others are still not identified. The
group theory will be used to describe the symmetry characteristics
of　the SF and SFT， to predict the possible transition phases in Fe
Mn-Si based alloys and to evaluate their stabilities based on
thermodynamic consideration.

　　2.Symmetry of planar stacking faults
　　Stacking fault as a kind of planar defects is not a simple plane，
but actually is a three-dimensional-structured plane with
two-dimensional period. Because of its very low SFE (several mJ/m2)
and， thus， its rather wide extension in Fe-Mn-Si based alloys， the
stacking fault belongs to this kind of specific plane. Therefore，
the layer group in symmetry groups can be suitably used for
studying the symmetry characteristics of such stacking
faults.

　　2.1.Layer group
　　Crystal symmetry group includes point group， plane group， layer
group and space group besides staff group， color group and so on.
Among them， layer group describes the symmetry group of two-plane
objects with double-layer structure which is different from
two-dimensional plane group. For the two-dimension situation， 17
kinds of plane groups can be deduced by means of operations
including rotation transformation (one- to six-fold axes except the
five-fold one)， reflected plane (m) and translation. When a single
plane changes into double， an inversion center (i) and a rotating
inversion as new operations lead to 80 kinds of layer groups with
the definition of space group on the basis of plane group. All
these layer groups attributing to four crystal systems (rectangle，
rhemble， tetragonal and hexagonal)
　　……