Accession Number : AD0714819

Title :   Cyclic Yield Behavior of Polycrystalline Niobium.

Descriptive Note : Technical rept.,

Corporate Author : IOWA UNIV IOWA CITY DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Agrawal ,Satish K. ; Stephens,Ralph I.

Report Date : OCT 1970

Pagination or Media Count : 31

Abstract : Previous investigations showed that the room temperature upper and lower yield point stress of b.c.c. iron and molybdenum can be completely removed by initially 'elastic' cyclic stressing above the fatigue limit. The research described shows the upper and lower yield point stress in niobium can also be removed under these same conditions. The cyclic stress-strain curve of niobium was found to cyclically strain soften at small strain amplitudes and cyclically strain harden at larger strains. Under constant cyclic strain amplitudes in the inelastic region niobium cyclically strain hardens and quickly reaches a stable hysteresis loop. The described cyclic yield point behavior was explained in terms of localized cumulative multiplication of mobile dislocations. (Author)

Descriptors :   (*NIOBIUM, FATIGUE(MECHANICS)), TENSILE PROPERTIES, HYSTERESIS, STRAIN(MECHANICS), DISLOCATIONS

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE