CRITICAL STRESSES FOR SLIP, TWINNING, AND CLEAVAGE IN SINGLE CRYSTALS OF IRON

An X-Ray, optical and metallographic study of the stresses for--and mechanisms of--slip, twinning and fracture in single crystals of iron prepared from decarburized mild steel has been made. The selection of the glide ellipse has been found to be a function of the relative difficulty of atom motions at various positions along a (111); this function being affected by temperature and distribution of stress. A critical shear stress criterion applies. Twinning has been found to occur on (112) type planes and in (111) directions below -170 deg C. as predicted by a critical shear stress law, mutatis mutandis. The twinning stress is greatly affected by slip. Brittle fracture could be accounted for by a critical normal stress theory within wide limits of error. Ductile fractures predominated for specimens where a cleavage plane, (001), was more than 65 degrees axis. Various effects of prestraining were observed.

• Corporate Authors:

  Carnegie Mellon University

  Wean Hall 4323
  5000 Forbes Avenue
  Pittsburgh, PA  United States  15213-3890

  Ship Structure Committee

  National Academy of Science, 2101 Constitution Avenue, NW
  Washington, DC  United States  20418
• Authors:
  • Cox Jr, J J
• Publication Date: 1954-2-1

Media Info

• Features: References;
• Pagination: 141 p.

Subject/Index Terms

• TRT Terms: Cleavage fracture; Cracking; Fracture mechanics; Metallography; Stresses
• Identifier Terms: Ship Structure Committee
• Uncontrolled Terms: Stress concentration
• Subject Areas: Marine Transportation; Materials;

Filing Info

• Accession Number: 00331009
• Record Type: Publication
• Source Agency: Ship Structure Committee
• Report/Paper Numbers: SSC- 66 Final Rpt.
• Contract Numbers: NObs-50230
• Files: TRIS
• Created Date: May 21 1981 12:00AM