SYMPOSIA PAPER Published: 01 January 1950

X-ray Study of the Sigma Phase in Various Alloy Systems


This paper presents a critical review of the X-ray diffraction data of the sigma phase in the binary alloys of iron, cobalt, nickel, chromium, and vanadium. Although the crystal structure of the sigma phase is still unknown, a tentative tetragonal unit cell is suggested to describe the structure, at least as a first approximation. On the basis of this cell the lattice parameters of the various binary sigma phases are computed. The case of a ternary sigma solid solution in the iron-chromium-molybdenum system is also discussed and the influence of molybdenum on the lattice parameter of sigma is described. A short discussion is given on the occurrence of the sigma phase in binary alloys and its relation to atomic diameter and crystal structure of the two component metals.

Author Information

Duwez, Pol
California Institute of Technology, Pasadena, Calif.
Baen, Spencer, R.
California Institute of Technology, Pasadena, Calif.
Price: $25.00
Contact Sales
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Developed by Committee: E04
Pages: 48–60
DOI: 10.1520/STP46103S
ISBN-EB: 978-0-8031-6741-4
ISBN-13: 978-0-8031-6506-9