Accession Number : AD0819194

Title :   FATIGUE OF METAL CRYSTALS--PART II. EXTENSION OF FATIGUE LIFE OF CRYSTALS THROUGH CONTROL OF SUBSTRUCTURE.

Descriptive Note : Final rept. 1 Mar 66-31 May 67,

Corporate Author : RUTGERS - THE STATE UNIV NEW BRUNSWICK NJ BUREAU OF ENGINEERING RESEARCH

Personal Author(s) : Weissmann, S. ; Greenhut, V. ; Park, B. K. ; Levine, E.

Report Date : JUN 1967

Pagination or Media Count : 7

Abstract : The intrinsic fatigue life of aluminum single crystals was extended by alternating the cycling between high and low strain amplitudes. It was shown that the life could be extended 50%-75% by the application of a multi-stage cycling program which prevented an excessive build-up of lattice defects induced by high-strain cycling. The fatigue life of aluminum crystals with transverse boundaries was also extended by annealing the high-strained regions during fatigue. The interconnection between surface topography and slip activity in single crystals and polycrystalline specimens of silver was investigated. A correlation between the surface striations and the activity on the primary glide plane was established. Cross-slip did not appear to contribute greatly to the striation formation.

Descriptors :   (*FATIGUE(MECHANICS), SINGLE CRYSTALS), (*ALUMINUM, SINGLE CRYSTALS), (*SILVER, CRYSTALS), ANNEALING, STRAIN(MECHANICS), GRAIN STRUCTURES(METALLURGY), GRAIN BOUNDARIES.

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE