Development of surface nano-crystallization in alloys by surface mechanical attrition treatment (SMAT)

Nanometer-sized grain structures that exhibit a large number of grain boundaries on the surface of a bulk material demonstrate excellent properties relative to their coarse-grained (CG) equivalents. Surface modification using surface mechanical attrition treatment (SMAT) is an option that cab be used to tailor the corrosion, tribological, mechanical, and chemical reaction properties of a surface. SMAT is an effective route to create the nanostructured surface layer. The SMAT process has unique advantages compared with the other coating and deposition techniques for surface nanocrystallization. For example, SMAT does not alter the chemical composition of the nanocrystalline surface layer in the matrix. In addition, SMAT has been demonstrated to activate the material surface layer by surface modification and enhance the atomic diffusivity. This article presents a review of the advantages offered by the SMAT technique for the creation of high performance surface layers. The influence of the created nanocrystalline layer on mechanical, physical, and chemical properties is assessed. Developments and the current status of the surface nanolayer that are formed are evaluated from a physical approach. Finally, prospects for the future development of grain refinement on the surface of a material matrix and potential applications are presented

A review on hybrid nanolaminate materials synthesized by deposition techniques for energy storage applications

Nanostructured materials such as nanocomposites and nanolaminates are currently of intense interest in modern materials research. Nanolaminate materials are fully dense, ultra-fine grained solids that exhibit a high concentration of interface defects. They may be developed for engineering applications that take advantage of enhanced mechanical properties or for devices such as energy storage and memory storage capacitors. Nanolaminates can be grown using atom-by-atom deposition techniques that are designed with different stacking sequences and layer thicknesses. The properties of fabricated nanolaminates depend on their compositions and thicknesses. These can be demonstrated within the synthesis process by thickness control of each layer and interfacial chemical reaction between layers. In fact, dielectrics with the formed thin layer have efficient dielectric constant and high insulation characteristics. Dielectric materials with giant dielectric constants can be fabricated as modified single, binary and perovskite oxides. A review of the advantages offered by nanolaminate structures for high performance energy storage devices is presented. Developments of dielectric materials that are formed from a thin layer approach are evaluated. The influence of the interface layer on the dielectric constant of nanolaminate films is assessed from the perspective of conferring a giant dielectric constant and high insulation characteristics. The incorporation of dopants and site-engineering techniques, as well as layer-by-layer structures, which can both be suitable for improving dielectric properties of dielectric nanolaminates, is detailed. Finally, the current status and development of artificial dielectric materials for high performance energy storage devices formed by dielectric nanolaminates are presente