Peening

About: Peening is a research topic. Over the lifetime, 5538 publications have been published within this topic receiving 73073 citations.

Eddy Current Assessment of Near-Surface Residual Stress in Shot-Peened Nickel-Base Superalloys

Abstract: It is shown in this paper that, in contrast with most other materials, shot-peened nickel-base superalloys exhibit an apparent increase in eddy current conductivity at increasing inspection frequencies, which can be exploited for nondestructive residual stress assessment of subsurface residual stresses. It has been found that the primary reason why nickel-base superalloys, which are often used in the most critical gas-turbine engine components, lend themselves easily for eddy current residual stress assessment lies in their favorable electro-elastic behavior, namely that the parallel stress coefficient of the eddy current conductivity has a large negative value while the normal coefficient is smaller but also negative. As a result, the average stress coefficient is also large and negative, therefore the essentially isotropic compressive plane state of stress produced by most surface treatments causes a significant increase in conductivity parallel to the surface. The exact reason for this unusual behavior is presently unknown, but the role of paramagnetic contributions cannot be excluded, therefore the measured quantity will be referred to as “apparent” eddy current conductivity. Experimental results are presented to demonstrate that the magnitude of the increase in apparent eddy current conductivity correlates well with the initial peening intensity as well as with the remnant residual stress after thermal relaxation.

Warm Laser Shock Peening Driven Nanostructures and Their Effects on Fatigue Performance in Aluminum Alloy 6160

Abstract: Warm laser shock peening is an innovative manufacturing process that integrates laser shock peening and dynamic aging to improve materials' fatigue performance. Compared to traditional laser shock peening (LSP), warm laser shock peening (WLSP) - i.e., LSP at elevated temperatures - provides better performance in many aspects. WLSP can induce nanoscale precipitation and high density dislocation arrangement, resulting in higher surface strength and lower surface roughness than LSP, which are both beneficial for fatigue life improvement. Due to pinning of the dislocation structure by nanoscale precipitates - so-called dislocation pinning effects - the relaxation of residual stress and surfaces dislocation arrangement is significantly reduced. In this study, AA6061 alloy is used to evaluate the WLSP process. It is found that the fatigue life improvements after WLSP are not only caused by large compressive residual stress and high density dislocations but also by the higher stability of the residual stresses and surface strength during cyclic loading.

Characterization of Plastic Deformation Induced by Microscale Laser Shock Peening

Abstract: Electron backscatter diffraction (EBSD) is used to investigate crystal lattice rotation caused by plastic deformation during high-strain rate laser shock peening in single crystal aluminum and copper sample on (I 10) and (001) surfaces New experimental methodologies are employed which enable measurement of the in-plane lattice rotation under approximate plane-strain conditions Crystal lattice rotation on and below the microscale laser shock peened sample surface was measured and compared with the simulation result obtained from FEM analysis, which account for single crystal plasticity The lattice rotation measurements directly complement measurements of residual strain/stress with X-ray micro-diffraction using synchrotron light source and it also gives an indication of the extent of the plastic deformation induced by the microscale laser shock peening