Accession Number:

ADA622643

Title:

Mechanisms of Residual Stress Generation in Mechanical Surface Treatment: the Role of Cyclic Plasticity and Texture

Descriptive Note:

Final rept. 1 Jun 2012-31 May 2015

Corporate Author:

OPEN UNIV MILTON KEYNES (UNITED KINGDOM)

Report Date:

2015-08-24

Pagination or Media Count:

49.0

Abstract:

This project investigated the response of two aluminum alloys to laser shock peening, studying the effects of hardening response through different heat treatments of the same alloy and the effects of crystallographic texture. The hardness of the material after peening was characterized by the nanoindentation technique, and the residual stresses were characterized by the incremental hole drilling technique. The effect of laser peening parameters on the magnitude, depth, and the uniformity of the induced hardness and residual stress was investigated. The number of peen layers has a significant effect on the hardness as well as the residual stress response. The T351 material showed an increase in hardness for up to 4 layers of peening which then saturated with further increase of power density and number of layers. However, an apparent softening effect was observed for the T39 alloy at higher energies. The effect of texture on the residual stresses generated by LSP was also studied. An AIG2099 an AIGLi alloy extruded TGbar was used that has strong fibre texture in the web section and a weak rolling texture in the flange section. Results show evidence of the influence of preferred crystallographic orientation on the depth and magnitude of the induced residual stress.

Subject Categories:

  • Properties of Metals and Alloys
  • Manufacturing and Industrial Engineering and Control of Production Systems
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE