Premium
Crystallography of the Martensitic transformation in Indium‐Thallium Alloys
Author(s) -
Schumann H.
Publication year - 1982
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170170824
Subject(s) - indium , tetragonal crystal system , martensite , thallium , crystallography , materials science , crystal twinning , single crystal , diffusionless transformation , stack (abstract data type) , ferroelasticity , diffraction , metastability , condensed matter physics , stress (linguistics) , chemistry , crystal structure , metallurgy , optics , microstructure , optoelectronics , ferroelectricity , dielectric , physics , organic chemistry , computer science , programming language , linguistics , philosophy
On cooling a single crystal of Indium containing 20.75 atomic per cent Thallium may transform martensitically by the migration of a single interface, covering the whole cross‐section, from the high temperature face‐centred cubic β‐structure to the facecentred tetragonal α‐structure. Applied external mechanical stress is able to reverse the direction of interface motion during transformation. The α‐martensite consists of a stack of fine parallel twins which are suficiently wide to be visible under an optical microscope. There are no longrange stresses, provided the twins have mean thickness ratio 1.6:1. By extension or compression the whole specimen may undergo a conversion into one or the other orientation by movement of the twin boundaries, leading to ferroplasticity or ferroelasticity. The geometry and crystallography of and the effects of external stresses on the β → α transformation have been calculated on the basis of the phenomenological crystallographic martensite theory.