Accession Number : AD0716573

Title :   Direct Studies of Fracture Mechanisms in Metals at Highest Magnifications.

Descriptive Note : Technical rept.,

Corporate Author : VIRGINIA UNIV CHARLOTTESVILLE RESEARCH LABS FOR THE ENGINEERING SCIENCES

Personal Author(s) : Bauer,Robert W. ; Lyles,Robert L. , Jr. ; Wilsdorf,Heinz G. F.

Report Date : DEC 1970

Pagination or Media Count : 35

Abstract : Thin silver single crystals and polycrystalline foils of type 304 stainless steel in both the solution treated and sensitized condition were strained to fracture inside a high voltage electron microscope. The specimens ranged in thickness from 0.5 to 2 microns. The design of a micro straining tensile device and techniques of specimen preparation are discussed. Results indicate that bulk fracture mechanisms are operative in these materials. Necking, shearing, formation and coalescence of holes, thinning ahead of propagating crack, and the dislocation structure in plastic zone preceding the crack are presented and discussed. (Author)

Descriptors :   (*STAINLESS STEEL, FRACTURE(MECHANICS)), (*SILVER, FRACTURE(MECHANICS)), FOILS(MATERIALS), CRACK PROPAGATION, SINGLE CRYSTALS, ELECTRON MICROSCOPY, STRAIN(MECHANICS)

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE