THE EFFECTS OF SURFACE LAYER ON PLASTIC DEFORMATION AND CRACK PROPAGATION

The rate of crack propagation was measured in three materials--aluminum 2014-T6, titanium (6Al-4V). and 4130 steel. Cyclic loading tests were performed at room temperature with the ratio of minimum to maximum stress intensity K(Min)/K(Max) = 0.25. Center-cracked and Ripling specimens were used for plane stress testing while compact tension (CT) specimens were used for plane strain testing. The effect of prestress and surface layer elimination treatment was investigated. A significant reduction in the crack propagation rate was observed with this treatment. The improvement was maximum at low stress intensity values both in plane stress and plane strain conditions. The optimum improvement was observed in specimens that were prestressed just below the yield and the surface removed.

  • Supplemental Notes:
    • This project was done for Army Materials and Mechanics Research Center, Watertown, Massachusetts, 02172, under ARPA Order 188-0-7400.
  • Corporate Authors:

    Martin Marietta Corporation

    P.O. Box 179
    Denver, CO  USA  80201
  • Authors:
    • Kramer, I R
    • KUMAR, A
  • Publication Date: 1971-8

Media Info

  • Features: References;
  • Pagination: 59 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00024799
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: AMMRC CR 71-2/2
  • Contract Numbers: DAAG46-70-C-0102
  • Files: TRIS
  • Created Date: Jan 21 1972 12:00AM