THE SUBSTRUCTURE OF PLASTICALLY DEFORMED NICKEL (thesis)

Technical Report · Mon Apr 01 04:00:00 EST 1963

OSTI ID:4678956

Nolder, R L

>Transmission electron microscopy techniques were used to study the substructure of pure nickel deformed under static and shock loading conditions. The shock loading was carried out under originally ambient temperature conditions. Loads ranging from 70 to 700 kilobars. Static loading involved compressive loading at the ambient temperature and tensile loading at temperatures ranging from 4 deg K to the ambient temperature. A dislocation cell structure was found in all statically loaded specimens, as was observed previously, and in specimens shock loaded up to 250 kilobars. Microtwinning was observed for the first time in nickel shock loaded at 350 kilobars and higher. It was found that under initially ambient temperature conditions the energy input per unit volume was inversely proportional to the square of the cell diameter. A possible explanation for this was proposed, making use of Kuhlmann-Wilsdorf's theory for work hardening in which the energy required to bow out dislocation segments was equated to the inverse square of an average dislocation segment's length. A similar analysis was used to explain twinning. By making use of both analyses a quantitative relation between the average cell diameter and the average segment length was predicted which seemed consistent with observations. A prediction of the ratio between the rigidity modulus and the work hardening coefficient in Stage II of work hardening was consistent with actual measurement obtained from published data. It is proposed that this type of analysis should be applied to other metal systems. (auth)

• Research Organization: California. Univ., Berkeley. Lawrence Radiation Lab.
• DOE Contract Number: W-7405-ENG-48
• NSA Number: NSA-17-032576
• OSTI ID: 4678956
• Report Number(s): UCRL-10778
• Country of Publication: United States
• Language: English

Related Subjects

CONFIGURATION
CREEP
DEFECTS
DEFORMATION
DISLOCATIONS
ELECTRON MICROSCOPY
HARDENING
HARDNESS
LATTICES
LOW TEMPERATURE
METALS, CERAMICS, AND OTHER MATERIALS
NICKEL
TWINNING