Accession Number:

AD0731825

Title:

The Effects of Surface Layer on Plastic Deformation and Crack Propagation

Descriptive Note:

Semiannual rept.

Corporate Author:

MARTIN MARIETTA AEROSPACE DENVER CO

Personal Author(s):

Report Date:

1971-08-01

Pagination or Media Count:

70.0

Abstract:

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 sub minK sub 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.

Subject Categories:

  • Metallurgy and Metallography
  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE