Peening

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

High spatial resolution, high energy synchrotron x-ray diffraction characterization of residual strains and stresses in laser shock peened Inconel 718SPF alloy

Abstract: Laser shock peening (LSP) is an advanced surface enhancement technique used to enhance the fatigue strength of metal parts by imparting deep compressive residual stresses. In the present study, LSP was performed on IN718 SPF alloy, a fine grained nickel-based superalloy, with three different power densities and depth resolved residual strain and stress characterization was conducted using high energy synchrotron x-ray diffraction in beam line 1-ID-C at the Advanced Photon Source at the Argonne National laboratory. A fine probe size and conical slits were used to non-destructively obtain data from specific gauge volumes in the samples, allowing for high-resolution strain measurements. The results show that LSP introduces deep compressive residual stresses and the magnitude and depth of these stresses depend on the energy density of the laser. The LSP induced residual stresses were also simulated using three-dimensional nonlinear finite element analysis, with employment of the Johnson-Cook model for describing the nonlinear materials constitutive behavior. Good agreement between the experimental and simulated data was obtained. These various results are presented and discussed.

The investigation of laser shock peening effects on corrosion and hardness properties of ANSI 316L stainless steel

Abstract: Laser shock peening (LSP) is known as a post processing surface treatment which can improve the mechanical properties of some materials. Shock waves are generated by confining the laser-induced plasma to cause a large pressure shock wave over a significant surface area. In the present study, effects of LSP on the electrochemical corrosion and micro hardness properties of 316L stainless steel alloy were investigated by changing the laser parameters such as the laser spot size, the average number of impacts, and the laser intensity. Since laser parameters do not cover the desired region of LSP, we have to use the proper design of experiment method, in which the D-optimal design of MATLAB was selected. Results revealed that by increase in irradiance, number of impacts and spot size of laser beam, improvement in the surface micro hardness, and corrosion resistance is achieved. Also, due to unexpected drop into the outcome of our experiments, it was found that the contamination of the transparent overlay and reduction of the absorption coefficient of the absorbent layer play a key role to reduce the efficiency of the mechanical impacts. So, by changing the experimental conditions, even better results are expected.

Improvement in cavitation erosion resistance of AA5083 aluminium alloy by laser shock processing

Abstract: Aluminium alloys are commonly used to manufacture the components that service under cavitation erosion environment. However, their poor cavitation erosion performance results in a significant reduction in their service life. In this study, a novel surface treatment method for improving cavitation erosion resistance by laser shock processing (i.e. laser shock peening with ablative coating (LSP) and laser shock peening without ablative coating (LSPwC)) was proposed. The microstructure, microhardness and residual stress of AA5083 aluminium alloy after laser shock processing were investigated. The cavitation erosion experiments were performed by ultrasonic cavitation. The cumulative mass loss, maximum surface damage depth, surface roughness and eroded surface morphologies during the cavitation erosion tests were characterized. The results indicate that laser shock processing can lengthen the incubation period and decrease the mass loss. The cavitation erosion resistance of LSP and LSPwC specimens is about 1.45 and 2.13 times that of substrate after 300 min cavitation erosion test, respectively. The eroded surface of substrate shows more serious damage morphology than that of treated specimens. The enhancement of cavitation erosion resistance for treated AA5083 aluminium alloy is ascribed to the refined grain and surface compressive residual stress, which can hinder the crack initiation and propagation, thereby inhibiting material spalling during cavitation erosion.