Results 111 to 120 of about 882,821 (145)

The Sigma Phase

International Materials Reviews, 1966
AbstractThe sigma phase, which occurs in transition-metal alloy systems, is of interest in both the technological and the theoretical field of alloy formation. In the former, the sigma phase is important because of its occurrence, with generally deleterious effects, in stainless and other high-alloy steels, while in the latter case a knowledge of the ...
E. O. Hall, S. H. Algie
openaire   +1 more source

Dense Delta-Sigma Phased Arrays

IEEE Transactions on Antennas and Propagation, 2013
The high cost of high-resolution phase shifters required to maintain precise control over the array beam pattern in traditional phased arrays preclude their use in a variety of emerging millimeter-wave applications. We develop a phased array architecture that obviates the need for such precise phase shifters, based on the use of sub-half-wavelength ...
James D. Krieger, Chen-Pang Yeang, Gregory W. Wornell   +2 more
openaire   +1 more source

Sigma-phase in duplex-stainless steels

Zeitschrift für Metallkunde, 2004
Abstract The ferritic-austenitic duplex-steels have a very complex precipitation and transformation behaviour, which requires professional treatment. Especially the precipitation of the σ-phase causes considerable changes with regard to the mechanical as well as the corrosive properties, which are to be considered during the treatment of
Michael Pohl, Oliver Storz
openaire   +2 more sources

Sigma Phase in Tungsten-Rhenium Alloys. I

Materials and Manufacturing Processes, 1996
Abstract In developing tungsten alloys for service both above the recrystallization temperature and below room temperature the main task is to make an alloy, which in addition to having a low ductile to brittle transition temperature in the recrystallized condition can readily be manufactured into various configurations.
Boris D. Bryskin, Jan-C. Carlén
openaire   +1 more source

SIGMA-SAFE: A phase diagram approach to the sigma phase problem in ni base superalloys

Metallurgical Transactions A, 1978
A new procedure for evaluating the sigma phase precipitation tendency of superalloys has been developed. It is called SIGMA-SAFE. Phase diagrams are used to determine the degree of super saturation with respect to precipitation of the sigma phase as a function of temperature and alloy compositions.
E. S. Machlin, JOEY Shao
openaire   +1 more source

Sigma-phase in steel 1Kh20N14S2

Metal Science and Heat Treatment of Metals, 1961
1. Dispersion hardening of steel 1Kh20N14S2 at 650°C occurs in two stages. The first stage lasting up to 500 hrs is characterized by the precipitation of secondary carbides Me23C6 and their coalescence, principally along austenite grains. The second stage is connected withσ-phase formation. 2.
V. S. Lyashenko, V. N. Bykov, V. A. Rudenko   +2 more
openaire   +1 more source

Sigma-Phase in Transitional Metal Alloys

Nature, 1951
THE existence of a phase isomorphous with the sigma-phase of the iron–chromium system has now been proved in a number of other alloys containing transitional elements. It has been observed in the following systems:
openaire   +2 more sources

Poly-phase sigma-delta modulation

IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, 1997
A new circuit is described for the implementation of analog sigma-delta modulation. It is based upon the use of a poly-phase sampler with the aim of obtaining high over-sampling ratios at low clock frequencies. A detailed analysis of second-order systems is made to predict its performance.
openaire   +1 more source

Sigma Phase in Vanadium–Nickel Alloys

Nature, 1952
AN X-ray examination has been made of a vanadium–nickel sigma phase single crystal containing 60 atomic per cent vanadium. The crystal was of irregular shape and plate-like form, the two larger dimensions being greater than ½ mm. Laue and rotation photographs using copper radiation showed that the unit cell was tetragonal with a = 8.95 kX. and c = 4.63
W. B. PEARSON, J. W. CHRISTIAN
openaire   +1 more source

Formation of sigma-phase in alloy KhN65VMTYu

Metal Science and Heat Treatment, 1987
1. Formation of σ-phase in high-temperature alloy KhN65VMTYu is governed to a considerable degree by its chemical composition. 2. Calculation of the chemical composition by the Phacomp method makes it possible to predict quite accurately the probability of σ-phase formation from the number of electron vacancies (Nv). For alloy KhN65VMTYu
L. S. Bulavina, I. N. Mel'kumov
openaire   +1 more source