Mechanical properties of alpha-neptunium: hardness and elastic moduli

Conference · Tue Jan 01 04:00:00 EST 1974

OSTI ID:4142113

Merz, M D; Kjarmo, H E

A study of hardness and elastic moduli of $alpha$-neptunium was conducted. The hardnesses at 203, 240 and 298$sup 0$K were 418, 395, and 346 dph, respectively. The high hardnesses were attributed to the low symmetry of $alpha$-neptunium and the large number of twins in the microstructure. Unusual deformation twinning and slip were observed near the hardness indentations. A second twinning mode, in addition to the reported (110) mode, was suggested by the observations. This twinning was characterized by very narrow, straight twins in contrast to the wide, highly curved twins observed previously in polycrystalline $alpha$-neptunium. An ultrasonic method was used to measure sound velocities at 77 to 373$sup 0$K. Elastic moduli and Poisson's ratio were calculated from the sound velocities. The room temperature values for the moduli were: B = 11.7 x 10$sup 11$ dyne/cm$sup 2$; G = 8.28 x 10$sup 11$ dyne/cm$sup 2$; and sigma = 0.22. The values were very nearly the same as the reported moduli of $alpha$-uranium. (auth)

• Research Organization: Battelle Pacific Northwest Labs., Richland, Wash. (USA)
• DOE Contract Number: AT(45-1)-1830
• NSA Number: NSA-33-001235
• OSTI ID: 4142113
• Report Number(s): BNWL-SA--5324; CONF-750915--17
• Country of Publication: United States
• Language: English

Related Subjects

*NEPTUNIUM-ALPHA-- MECHANICAL PROPERTIES
360103* --Materials--Metals & Alloys--Mechanical Properties
DEFORMATION
ELASTICITY
HARDNESS
LOW TEMPERATURE
MEDIUM TEMPERATURE
MICROSTRUCTURE
N50230* --Metals
Ceramics
& Other Materials--Metals & Alloys--Properties
Structure & Phase Studies
POISSON RATIO
SOUND WAVES
TWINNING
VELOCITY
VERY LOW TEMPERATURE