Determination of the dislocation density in deformed iron whiskers by positron annihilation

Conference · · TMS (The Metallurgical Society) Paper Selection; (USA)

OSTI ID:5368458

Waber, J T; Brittain, J ^[1]

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1. Northwestern Univ., Evanston, IL (USA)

The positron lifetime spectra and changes in the Doppler Broadening of the gamma rays which result from the positron being trapped by and annihilating in the defect have been used to determine the edge and screw dislocation content of iron whiskers deformed in torsion. Scanning electron microscope pictures have been taken of the etch pits in deformed whiskers following exposure to the etchant recommended by Schemenski, Beck and Fontana. Arrays of etch pits associated with <111> type dislocations were found to be essentially perpendicular to the axis of the whiskers. On the basis of this observation it is reasonable to assign the lifetime of 142 psec. to positron annihilating while trapped in screw dislocations.

• OSTI ID: 5368458
• Report Number(s): CONF-840909--
• Conference Information: Journal Name: TMS (The Metallurgical Society) Paper Selection; (USA) Journal Volume: 56
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals &amp; Alloys-- Structure &amp; Phase Studies
ANNIHILATION
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BASIC INTERACTIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DEFORMATION
DISLOCATIONS
EDGE DISLOCATIONS
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
GAMMA RADIATION
INTERACTIONS
IONIZING RADIATIONS
IRON
LEPTONS
LINE DEFECTS
METALS
POSITRONS
RADIATIONS
SCREW DISLOCATIONS
TORSION
TRANSITION ELEMENTS