Formation of bcc non-equilibrium La, Gd, and Dy alloys and the magnetic structure of Mg-stabilized. beta. Gd and. beta. Dy

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5306258

Herchenroeder, J W

The high temperature bcc allotrope of a rare earth metal has the potential for substantially different magnetic properties than the room temperature hexagonal (hcp or dcp) counterpart because of its more symmetrical crystal field. The stabilization by alloying and quenching of this bcc phase was studied for La-M alloys where M is a non-rare earth metal from Group II or III. The factors influencing the stabilization, such as size of M and quench rate, are discussed. {gamma}La (bcc) could be retained over a composition range around the eutectoid composition by Mg or Cd alloying. A comparison of T{sub o} curves of the various alloy systems suggest that the eutectoid temperature of the La-M system must be approximately equal to or less than a critical T{sub o} temperature of 515{degree}C if the bcc phase is to be retained by quenching. The thermal stability of {beta}Gd (bcc) was investigated by DTA and isothermal annealing. It was found to transform to an intermediate phase before reverting to the equilibrium phases in contrast to {gamma}La alloys which decompose directly on heating to the equilibrium phases. Bcc {beta}Gd and {beta}Dy stabilized by Mg additions exhibit spin glass-like behavior. Both systems show field cooling effects in the magnetic susceptibility which is indicative of spin freezing reactions.

• Research Organization: Iowa State Univ. of Science and Technology, Ames, IA (USA)
• OSTI ID: 5306258
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
DYSPROSIUM
DYSPROSIUM ALLOYS
ELEMENTS
GADOLINIUM
GADOLINIUM ALLOYS
LANTHANUM ALLOYS
MAGNESIUM ADDITIONS
MAGNESIUM ALLOYS
MAGNETIC PROPERTIES
METALS
PHASE STUDIES
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
RARE EARTHS
STABILIZATION