Neutron scattering studies of premartensitic phenomena

Conference · Sun Jan 01 00:00:00 EST 1989

OSTI ID:5526336

Shapiro, S M

Elastic neutron diffraction and inelastic neutron scattering are ideal techniques for studying premartensitic behavior in metallic alloys. By necessity, real, bulk samples are probed replete with their intrinsic defects. Also, because of the properties of the neutron it is straightforward to probe the behavior of the phonon modes away from the zone center which is probed in the normal ultrasonic techniques. A wide variety of alloys exhibiting martensitic transformations have been studied. It will be shown that most systems undergoing diffusionless transformations exhibit premartensitic behavior in that precursor effects are seen at temperatures well above the martensitic transformation temperature, T{sub M}. This behavior manifests itself in an anomalous temperature dependence of the energy of a particular phonon mode as the temperature approaches T{sub M}. The wavevector of this mode is frequently away from the zone center (i.e., q {ne} O). This softening is nearly always accompanied by elastic diffuse scattering at the same wavevector. Particular examples to be discussed are the alkali metals, {omega}-phase materials and Ni-based alloys. 34 refs., 9 figs.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 5526336
• Report Number(s): BNL-43179; CONF-8907114-2; ON: DE90000025; TRN: 89-024706
• Resource Relation: Conference: International conference on martensitic phase transformations (ICOMAT-89), Sydney (Australia), 3-7 Jul 1989
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALLOYS
NEUTRON DIFFRACTION
ALKALI METALS
MARTENSITE
NICKEL BASE ALLOYS
PHASE TRANSFORMATIONS
PHONONS
SCATTERING
TEMPERATURE DEPENDENCE
CARBON ADDITIONS
COHERENT SCATTERING
DIFFRACTION
ELEMENTS
IRON ALLOYS
METALS
NICKEL ALLOYS
QUASI PARTICLES
360102* - Metals & Alloys- Structure & Phase Studies
654003 - Radiation & Shielding Physics- Neutron Interactions with Matter