Accession Number : AD0666678

Title :   THE EFFECT OF VACUUM ON SURFACE DAMAGE IN FATIGUE.

Descriptive Note : Final scientific rept.,

Corporate Author : TEXAS UNIV AUSTIN ENGINEERING MECHANICS RESEARCH LAB

Personal Author(s) : Wilkov,M. A. ; Applewhite,B.

Report Date : DEC 1967

Pagination or Media Count : 29

Abstract : The environment at the surface is known to have a marked effect on the fatigue behavior of metals. In spite of considerable work on the relation between fatigue and environment almost nothing is known with certainty about the surface morphology and surface condition near the damage zones. The changes in both the surface topography and the dislocation structure, produced during fatiguing aluminum crystals in vacuum were investigated using electron microscopy and surface nucleation. It was found that the intrusions formed faster during fatigue in vacuum than in air, however, the width of the damage zone was reduced. The observation of enhanced nucleation on the slip lines in both specimens fatigued in vacuum exposed to air and then deposited and specimen fatigued in vacuum and deposited immediately indicated that the biggest difference in the surface damage was morphology rather than the condition of the oxide layer. (Author)

Descriptors :   (*ALUMINUM, FATIGUE(MECHANICS)), (*FATIGUE(MECHANICS), VACUUM), METALLURGY, SURFACE PROPERTIES, DISLOCATIONS, ELECTRON MICROSCOPY, NUCLEATION, STRESSES, CRACKS, GOLD

Subject Categories : Metallurgy and Metallography
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE