Crystal Structures and Phase Transformations in Indium Rich Solid Solutions

概要

論文の詳細を見る
The phase transformations and crystal structures in indium-rich alloys, such as In-Tl, In-Cd, In-Sn and In-Pb alloys, have been studied using X-ray diffraction topography, electron microscopy, and X-ray and electron diffraction supplemented by conventional metallographic techniques. The phase transformations were found to be classified into four groups : [a] fcc〓fct(c/a>1) transformation ; In-(18-30) at%Tl and In-(4.0-5.5) at%Cd alloys, [b] fcc〓fct(c/a<1) transformation; In-(28-36) at%Pb alloys, [c] fct (c/a<1)〓fco〓fct(c/a>1) transformation ; In-(12-16)at%Pb alloys, [d] fct(c/a<1) 〓fct(c/a>1) transformation ; In-(13-15)at%Sn alloys. These phase transformations, except for the fco〓fct(c/a>1) transformation, are of martensitic kind. These alloys show a banded surface relief when cooled to room or lower temperatures, the bands lying on {101} planes. When heated to moderate temperatures each alloy exhibits a shape memory effect which is associated with a reverse transformation of a low temperature phase to its high temperature one. The mechanism of phase transformation is discussed in terms of the soft phonon mode, considering a double shear process, and the structural transformations in indium-rich alloys examined are summarily explained on the basis of a phenomenological theory based on the Landau's theory of phase transformation.
東北大学の論文