Peening

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

Deforming TC6 titanium alloys at ultrahigh strain rates during multiple laser shock peening

Abstract: The deformation mechanism of TC6 titanium alloys at ultrahigh strain rates (>10 6 s −1 ) during multiple LSP was investigated. When nanosecond pulse and 1000 MW laser irradiated on the materials, the high pressure plasma shock wave was induced and ultrahigh strain rates response was caused in the material. The TEM observation of the surface layer indicates that a layer of nanocrystalline has been formed and is unevenly distributed after a single impact. Increasing impact times could provide longer time and more energy to dislocation movement which refines the grains into smaller size and makes the distribution uniform. The hardness of TC6 titanium alloy has been improved by a single laser shock peening, forming a severe plastic deformted layer with a depth of 200 μm. Increasing impact times will improve the hardness and effective depth. The XRD test shows that the position of diffraction peak did not show any change, but the Bragg diffraction peak was broadened. Dislocation activity is a prevalent deformation mechanism of TC6 titanium alloy in the grain refinement study.

Optimization of shot peening parameters by response surface methodology

Abstract: In this study, the shot peening parameters which directly influence the arc height of the Almen strip and its characteristics are optimized within the context of Almen intensity, surface roughness and surface hardness via response surface methodology. Determination of the Almen intensity by trial and error method depending on the experience of the technician (measuring the arc height of Almen strips by changing the parameters repeatedly for each shot peening process) makes the optimization approaches valuable. The optimization is considered to perform by selecting surface roughness and surface hardness as the responses in order to classify the shot peening processes by taking into consideration of wide range of plastic deformation level. The effect of input parameters air pressure, shot diameter and peening duration on the Almen intensity, surface roughness and surface hardness is to be determined by using ANOVA regression analysis. Based on the estimated models, optimum peening conditions are introduced via response optimizer. The model adequacy is verified by the confirmation tests.

In situ stress evolution during magnetron sputtering of transition metal nitride thin films

Abstract: Stress evolution during reactive magnetron sputtering of TiN, ZrN, and TiZrN layers was studied using real-time wafer curvature measurements. The presence of stress gradients is revealed, as the result of two kinetically competing stress generation mechanisms: atomic peening effect, inducing compressive stress, and void formation, leading to a tensile stress regime predominant at higher film thickness. No stress relaxation is detected during growth interrupt in both regimes. A change from compressive to tensile stress is evidenced with increasing film thickness, Ti content, sputtering pressure, and decreasing bias voltage.