T R Anantharaman
Articles written in Proceedings – Section A
Volume 55 Issue 2 February 1962 pp 121-129
The mechanism of sub-microscopic precipitation in an Al-Zn-Mg alloy selected for its maximum response to ageing has been studied by a standardized oxide-replica technique in a 100 kV. Philips Electron Microscope. Contrary to earlier conclusions, examination of the oxide replicas has been shown to reveal details of the precipitation process almost as clearly as the thin-foil transmission technique. The reported formation of spherical Guinier-Preston zones followed by the development of a Widmanstaetten pattern of precipitated platelets has been confirmed. The zones have, however, been shown to grow into the platelets and
Volume 58 Issue 5 November 1963 pp 314-325
Approximations employed so far in the evaluation of growth and deformation faulting in h.c.p. structures from integral and half-peak X-ray line breadths have been critically examined. An improved and yet simple procedure has been suggested to study faulting, mixed or otherwise, in h.c.p. structures. Necessary corrections for limitations of the measuring range have been worked out for integral and half-peak breadths over a wide range of growth and deformation fault parameters. The suggested procedure is illustrated by application to a study of faulting in spontaneously transformed cobalt powder.
Volume 61 Issue 4 April 1965 pp 230-236
New results on the impact of thermal and mechanical treatment of pure cobalt on the content of the hexagonal phase and densities of growth as well as deformation stacking faults have been presented. The significance of these results along with those obtained by earlier investigators has been discussed
Volume 61 Issue 6 June 1965 pp 340-367
The constitution of manganese-gallium alloys has been investigated, chiefly by thermal analysis and X-ray methods. The binary phase diagram has been established, displaying eight peritectic, three eutectoidal and two peritectoidal reactions. Ten intermediate phases have been recognized and the structures of six of them have been resolved. The details of the constitutional diagram have been discussed in relation to allied systems and in the light of the valency electron interactions.
Volume 64 Issue 5 November 1966 pp 261-274
Formulae for the Scherrer constant K
Volume 75 Issue 3 March 1972 pp 103-107
Extremely rapid solidification of a Ag-15 at.% Ge alloy results in the formation of a highly irregular structure. The individual grains consist of a lamellar mixture of close-packed structures with different stacking sequences (f.c.c. and h.c.p. phases as well as long-period stacking structures), superposed with a high density of randomly arranged stacking faults. It is concluded that the structure observed at room temperature may have formed by martensitic transformation of a metastable b.c.c. phase which is formed first upon solidification.