New possibilities for recrystallization study by X-Ray synchrotron radiation topography

Abstract

New possibilities provided to recrystallization studies by X‐ray synchrotron radiation topography are tested and a preliminary investigation is presented. Reerystallization experiments are carried out in front of the X‐ray synchrotron beam and topographs are made to observe the grain growth process. Firstly, the potentialities of this new technique are discussed and compared to those of previous methods (electron microscopy, photoemission‐electron microscopy …︁) then it is shown what it allows to reach: 1) visibility of growth defect formation, 2) visibility of growth defect evolution, 3) catching a sight of nucleation‐growth transition, 4) perhaps distinguishing structure differences between moving and stationary grain boundaries.

Ultra-high vacuum heating camera for in situ synchrotron radiation X-ray topographic studies

“…The first in situ studies of the recrystallization of aluminium that we have done, using synchrotron radiation X-ray topography, have quickly shown the interest of this new instrument (Gastaldi & Jourdan, 1978, 1979. However, the heating camera used (Gastaldi & Jourdan, 1978) had the major defect of preventing the observation of the recrystallization process above 623 K because topographs were rapidly loosing their contrast. After many tests we have been able to determine that this limitation was due to the thickness of the aluminium oxide layer at high temperature.…”

“…This was not possible with an electron microscope [with high-voltage electron microscope for aluminium-thickness about a few micrometres and observation field about l0 ~tm (Jouffrey, 1979)]. As has been shown by recrystallization studies for which new information has been brought (Gastaldi & Jourdan, 1978), the performances of the apparatus are convenient. The use of this camera would be profitable as well to study other phenomena in various materials (phase transition in quartz, in titanium, stress relaxation in epitaxial layers, precipitation, etc.).…”

“…As in previous topographic studies, made a posteriori (Gastaldi, Marzo & Jourdan, 1973) or in situ under ordinary vacuum (Gastaldi & Jourdan, 1978, 1979 a holding device for samples which minimizes stresses has been used. In this device, samples (25 x 15 x 0.8 mm) are held-between two points in a 'stirrup piece' and have been cut around the holding points with a spark-cutting machine (Gastaldi, Marzo & Jourdan, 1973).…”

Formation of faulted defects in copper by moving boundaries

“…Direct observation of the sequence of events involved in the formation of such defects at, and their subsequent detachment from, a moving boundary is not possible in experiments where bulk specimens are annealed to produce boundary movement and subsequently thinned for examination by transmission electron microscopy (TEM). Direct observations have been made on the movement of boundaries in bulk specimens using synchrotron X-ray topography [2], but the resolution attainable is insufficient to observe the detail of the defects generated and the processes involved in their formation.…”

Application of in situ synchrotron X-ray topography to the study of a solid-phase transformation: crystallography of the transition in pure titanium

“…Owing to experimental difficulties it has not been possible, except for the work of Brock ( 1955), to observe directly this transformation. The field of dynamic investigations of phase transitions, plastic deformations or solidphase growth has been opened with the high power of the synchrotron X-ray beam (Miltat, 1978: Gastaldi & Jourdan, 1978. During the present in situ study of the recrystallization process of titanium by synchrotron-radiation X-ray topography it has been possible to observe the :~fl transition.…”