Cracks Propagation as a Function of Grain Size Variants on Nanocrystalline Materials’ Yield Stress Produced by Accumulative Roll-Bonding

Abstract

Cracks are usually observed at the edge of materials deformed by accumulative roll bonding from conventional materials to nanostructure materials. The observed cracks then propagate in the materials during grain refinement. The cracks propagation affects the yield stress and the effective fracture energy of nanocrystalline materials. In this study, the impacts of crack propagation when measured as a function of grain size variants on nanocrystalline materials' yield stress are investigated for a material deformed by accumulative roll-bonding. The study employs experimental data and theoretical concepts of severe plastic deformation and cracks processes in nanocrystalline materials. The current studies also focus on nano-cracks that will not lead to rapid materials failure during grain refinement. The study revealed that crack propagation varied as a function of grain size variants during grain refinement. The study also revealed that nano-crack increased during the deformation of nanostructured materials. The study also revealed that the effective fracture energy decreased as grain refinement took place. The study revealed that nanomaterials yield stress decreased with the increase in effective fracture energy. The current study suggests a theoretical model that shows the generation of nanomaterials cracks during grain refinement as a function of grain size variants. In the model, the cracks propagate on nanocrystalline materials due to the compressive load applied to a material. The model predicts that the generation of cracks as functions of grain size variants impacts the energy level in nanocrystalline materials.

[Retracted] Application Value Analysis of Nanooptical Materials in Martial Art Single‐Kick Protective Equipment

“…This optimal microstructure exhibits more strain hardening than other machined materials studied. It can be said that reasonable grain size distribution and strain hardening help to improve the ductility of the material [15].…”

A Study to Improve the Efficiency and Performance of a Pelton Wheel using Potential Energy at Low Heads

“…We do not need a rocket scientist, an engineer, scientist, or a researcher to alert us about the current electricity energy challenges especially in South Africa and other African countries due to climate change that imminent to energy crisis [1][2][3][4][5][6][7][8][9][10][11][12]. Most often the available source of energy has several environmental implications such as pollution and destruction of the ozone layer which has led to global warming and climate change [1][2][3][4][5][6][7].…”

“…This has resulted to low generation of electric energy during summer or dry season in most Countries that use hydroelectric generation plant. With the current climate change, it is likely that this problem will become worst in dry season and energy generation will become more unstable [1][2][3][4][5][6][7][8][9][10][11]. From the research and through feasibility studies Pelton wheel is only efficient or stable in power generation when working at very high heads.…”

“…But it can be utilized for the (Low heads) and (High release) applications too by including a few alterations in plan. This sort of free-jet water turbine is to begin with presented by an American design named Lester Pelton in 1870 which has undergone several modifications to improve the system efficiency [1][2][3][4][5][6][7][8][9][10][11]. In deriving the theoretical model for the application to improve the Efficiency and Performance of a Pelton Wheel using Potential Energy at Low Heads.…”