The efficiency of tumble finishing as a final post-treatment for fatigue enhancement of notched laser powder bed fusion AlSi10Mg.

A hybrid post-treatment combining tumble finishing as a final step after shot peening and heat treatment was developed to alleviate the adverse effects of internal and surface defects on the fatigue performance of laser powder bed fusion AlSi10Mg samples. The effects of each post-treatment were investigated individually and synergistically on microstructure, surface morphology and roughness, hardness, residual stresses, porosity, and rotating bending fatigue behavior of V-notched AlSi10Mg samples. The results reveal that tumble finishing can highly reduce surface roughness by 28 and 32% compared to the as-built and heat-treated states while inducing extra surface layer hardening and compressive residual stresses.

3D Reality-Based Survey and Retopology for Structural Analysis of Cultural Heritage.

Cultural heritage's structural changes and damages can influence the mechanical behaviour of artefacts and buildings. The use of finite element methods (FEM) for mechanical analysis is largely used in modelling stress behaviour. The workflow involves the use of CAD 3D models and the use of non-uniform rational B-spline (NURBS) surfaces.

Introducing gradient severe shot peening as a novel mechanical surface treatment.

Shot peening is widely used for improving mechanical properties especially fatigue behavior of metallic components by inducing surface hardening, compressive residual stresses and surface grain refinement. In air blast shot peening, projection pressure and surface coverage (an index of peening duration) have been considered as major controlling process parameters; the combination of these parameters plays a critical role in the beneficial effects of shot peening. Generally in severe shot peening aimed at obtaining surface grain refinement, constant values of pressure are considered with different peening durations.

Evaluating the Homogeneity of Surface Features Induced by Impact-Based Surface Treatments.

Impact surface treatments are well-known for their efficiency in enhancing the mechanical properties of metallic materials, especially under cyclic loadings. These processes, which encompass a wide range of surface treatments based on repetitive impacts of tools of various types, induce surface plastic deformation, compressive residual stresses, and grain refinement alter the surface roughness as a side effect. Thus, it is essential to have suitable indexes to quantify the surface features caused by the typically random nature of these treatments.

Inclined and multi-directional surface impacts accelerate biodegradation and improve mechanical properties of pure iron.

Impact based surface treatments with adequate kinetic energy have favorable effects on promoting cell-substrate interactions, reducing bacterial adhesion, and enhancing fatigue performance of metallic biomaterials. Here, we used both numerical and experimental approaches to evaluate the potential of these treatments for addressing the major issue associated with the application of pure iron in biomedical implants, i.e.

Accelerated biodegradation and improved mechanical performance of pure iron through surface grain refinement.

Pure iron and its biocompatible and biodegradable alloys have a high potential to be used for temporary load bearing medical implants. Nevertheless, the formation of passive iron oxide and hydroxide layers, which lead to a considerably low degradation rate at the physiological environment, has highly restricted their application. Herein we used numerical and experimental methods to evaluate the effect of severe shot peening, as a scalable mechanical surface treatment, on adjusting the performance of pure iron for biomedical applications.

Effects of nanofeatures induced by severe shot peening (SSP) on mechanical, corrosion and cytocompatibility properties of magnesium alloy AZ31.

Unlabelled: The application of biodegradable magnesium-based materials in the biomedical field is highly restricted by their low fatigue strength and high corrosion rate in biological environments. Herein, we treated the surface of a biocompatible magnesium alloy AZ31 by severe shot peening in order to evaluate the potential of surface grain refinement to enhance this alloy's functionality in a biological environment. The AZ31 samples were studied in terms of micro/nanostructural, mechanical, and chemical characteristics in addition to cytocompatibility properties.

The influence of nanostructured features on bacterial adhesion and bone cell functions on severely shot peened 316L stainless steel.

Substrate grain structure and topography play major roles in mediating cell and bacteria activities. Severe plastic deformation techniques, known as efficient metal-forming and grain refining processes, provide the treated material with novel mechanical properties and can be adopted to modify nanoscale surface characteristics, possibly affecting interactions with the biological environment. This in vitro study evaluates the capability of severe shot peening, based on severe plastic deformation, to modulate the interactions of nanocrystallized metallic biomaterials with cells and bacteria.

Cell response to nanocrystallized metallic substrates obtained through severe plastic deformation.

Cell-substrate interface is known to control the cell response and subsequent cell functions. Among the various biophysical signals, grain structure, which indicates the repeating arrangement of atoms in the material, has also proved to play a role of significant importance in mediating the cell activities. Moreover, refining the grain size through severe plastic deformation is known to provide the processed material with novel mechanical properties.