Studies on the Effect of Laser Shock Peening Intensity on the Mechanical Properties of Wire Arc Additive Manufactured SS316L

This study examines the impact of laser shock peening (LSP) on the mechanical properties, microstructural features, and elemental distribution of stainless steel 316L (SS316L) produced using wire arc additive manufacturing (WAAM). The investigation focuses on significant changes in mechanical behavior, surface topography, and porosity following LSP treatment, comparing these results to the untreated condition. LSP treatment significantly enhanced the ultimate tensile strength (UTS) and yield strength (YS) of WAAM-fabricated SS316L samples. The UTS of the as-manufactured WAAM specimen was 548 MPa, which progressively increased with higher LSP intensities to 595 MPa for LSP-1, 613 MPa for LSP-2, and 634.5 MPa for LSP-3, representing a maximum improvement of 15.8%. The YS showed a similar trend, increasing from 289 MPa in the as-manufactured specimen to 311 MPa (LSP-1) and 332 MPa (LSP-2), but decreasing to 259 MPa for LSP-3, indicating over-peening effects. Microstructural analysis revealed that LSP induced severe plastic deformation and reduced porosity from 14.02% to 4.18%, contributing to the improved mechanical properties. Energy dispersive spectroscopy (EDS) analysis confirmed the formation of an oxide layer post-LSP, with an increase in carbon (C) and oxygen (O) elements and a decrease in chromium (Cr) and nickel (Ni) elements on the surface, attributed to localized pressure and heat impacts. LSP-treated samples exhibited enhanced mechanical performance, with higher tensile strengths and improved ductility at higher laser intensities. This is due to LSP effectively enhancing the mechanical properties and structural integrity of WAAM-fabricated SS316L, reducing porosity, and refining the microstructure. These improvements make the material suitable for critical applications in the aerospace, automotive, and biomedical fields

Design and development of Cu‐Al‐Mn‐Ni shape memory alloy coated optical fibre sensor for condition‐based monitoring of physical systems

Abstract Online fault detection, isolation and recovery using smart sensors play an important role in intelligent manufacturing system. Fibre optic sensors are very interesting for condition monitoring applications due to the advantage of this technology. Here, the experimental demonstration of Cu‐based shape memory alloy (SMA) coated optical fibre for temperature‐based sensing applications is reported. The benefit of Cu‐based SMA coated optical fibre over conventional metallic coating has been evaluated in the study. For consistent coating, an in situ fixture with a rotary drive setup has been designed and developed. Thermo optic test bench has been developed to study the actuation characteristics of the SMA coated optical fibre for varying current and voltage. Experiments were performed to investigate the light intensity in the SMA coated optical fibre at different actuation conditions. The displacement that takes place in the optical fibre due to the external temperature stimuli will create proportional intensity and wavelength shifts. The maximum average displacement of 4.9 mm has been achieved for Cu‐Al‐Mn‐Ni coated optical fibre. Results show variation in the optical fibre signal due to heating and cooling of the fibre from the applied electrical stimulus on Cu‐based SMA coating in the form of austenite to martensite transformation

Post-processing of wire-arc additive manufactured stainless steel 316 l bone staples using laser shock peening:a mechanical and antibacterial study

The paper presents the effect of post-processing with laser shock peening (LSP) on the mechanical and antibacterial properties of wire-arc additive manufactured (WAAM) SS316L bone staples. It is observed that the tensile strength and toughness of the WAAM-built SS316L bone staples improved significantly by LSP treatment, which is essential to their longevity and capacity to function under mechanical stress. The LSP-treated samples showed an enhanced presence of significant alloying elements like molybdenum, nickel, and chromium, which are essential for corrosion resistance, as well as a refined microstructure with fewer surface flaws. Furthermore, the antibacterial research showed that the LSP treatment gives the bone staples improved antibacterial qualities. A significant decrease in bacterial colonization was observed in the LSP-treated samples when compared across different periods (24, 48, and 72 h), suggesting the possibility of lower infection rates in clinical settings. SEM images displayed a reduction in biofilm formation with increasing LSP intensity, suggesting improved bacterial resistance due to surface smoothening and densification from LSP. This shows the effectiveness and significance of WAAM integrated with LSP to enhance the mechanical and antibacterial properties of SS316L bone staples, potentially leading to improved medical implants