Commercially pure nickel was processed by equal channel angular pressing (ECAP) through route Bc for 12 passes to obtain an ultrafine grained (UFG) microstructure and further subjected to an ultrasonic treatment (UST) which introduced a maximum amplitude equivalent to anormal stresses of 100 MPa in a steady state regime. It was observed that the microstructure of UFG Ni can be differently alter...

Abstract The exact calculations of the stress and strain distributions based on controlling equations for a forming process with large deformation are often difficult. To circumvent such difficulties, some analytical methods upper-bound analysis slip-line field theory have been established by making number simplifying assumptions regarding material properties modes. In this work an model was su...

Variation in microstructural features of 2024 aluminum alloy plastically deformed by equal channel angular pressing (ECAP) at room temperature, was investigated by X-Ray diffraction in this work. These include dislocation density dislocation characteristic and the cell size of crystalline domains. Dislocations contrast factor was calculated using elastic constants of the alloy such as C 11, C 2...

The main aim of the current project has been to produce a batch of bulk billets with ultrafine-grained (UFG) microstructure and enhanced strength made of two refractory metals such as tungsten and tantalum. To process bulk W billets with UFG structure having a long-length size more than 100 mm we have developed and successfully used a new approach based on a combination of equal angular pressin...

Despite extensive literature consisting of many excellent academic and practical papers, there are still many commonly heard fallacies in practice such as: “To aggregate risks, all I need are correlations”. “I assume dependence/independence, hence there is no copula”. “I need to use a Variance-Covariance approach with tail-end correlations to capture fat tails and tail dependence”. “The mere ex...

Recent developments in nanostructured products draw considerable attention to ultrafine grained materials. These materials are normally manufactured by different severe plastic deformation (SPD) methods. In the present study, analytical models and finite element method (FEM) are used to calculate strain imposed to a specimen that was deformed by equal channel angular pressing (ECAP). In additio...

The focus of this study was on the effect channel angle stress distribution in material aluminum alloy 5083. mechanical properties a mate- rial are related to grain size. Equal angular pressing (ECAP) is method for deforming materials such way that strong prop- erties formed while dimensions work piece stay fixed order make ultra-fine-grained materials. One parameters ECAP angle. It’s crucial u...

امروزه علاقه به اعمال سبک مربی گری در میان مدیران سازمانها حال رشد است. سازمان ها دنبال این روش مدیریتی هستند تا با استفاده از شایستگی های گری، نیروی انسانی خود را متعهد ساخته و بهبودعملکرد فردی سازمانی نائل آیند. وجود این، هیچ تحقیق یا ادبیاتی زمینه ندارد که کدامیک عوامل بیشترین بهبود عملکرد برای ویژه بانک بوجود می آورند. حاضر راستای پاسخگویی چالش، صورت جامع نظام مند تمامی شاخص هایی حوزه موثر ...