fabrication of ultrafine grained materials by imposing severe plastic deformation for improvement of mechanical and physical properties of metals has been the focus of many researches over the past few years. in this process, a sheet is subjected to repetitive shear deformation conditions by utilizing asymmetrically grooved and flat dies through alternate pressing. in this study, a 2mm thick co...

In this study, constraint groove pressing (CGP) process and ultrasonic assisted CGP (UCGP) process were investigated on the process forces, mechanical properties of the sheet, including hardness and tensile tests and grain size. Pure copper sheets were used as samples in this research. Samples were tested both with and without ultrasonic vibrations for mechanical properties and grain size up to...

In recent years, the fabrication of bulk materials with ultra fine grain sized materials processed by SPD methods. Different techniques have been used to introduce large plastic strains in to bulk metals such as Equal Channel Angular Pressing (ECAP) [1-3], Accumulative Roll Bonding (ARB) [4-7], Repetitive Corrugation and Straitening (RCS) [8,9], Constrained Groove Pressing (CGP) [5] and Constra...

On the basis of experimental and practical material it was determined that scratches were formed as a result of sliding of rough surface or sharp point along the body. In case of slight pressing narrow almost linear injuries occur in the form of chains which consist presumably of angle-shaped tears of epidermis with the bases directed to movement side. Considerable pressing results in continuou...

one of the most common methods for production of ultra fine grained materials is severe plastic deformation (spd). in this study, constrained groove pressing (cgp) and high pressure torsion (hpt) processes as effective methods of severe plastic deformation for the strain imposed on the pure copper were used. this paper presents the results of an experimental research, to review the influence of...

One of sheet severe plastic deformation (SPD) operation, namely constrained groove pressing (CGP), is investigated here in order to specify the optimum values for geometrical variables of this process on pure aluminium sheets. With this regard, two different objective functions, i.e. the uniformity in the effective strain distribution and the necessary force per unit weight of the specimen, are...

Deep-sea pressure vessels are specialized designed for automatic deployment from underwater to the surface. These find extensive applications in life-saving and transportation. Their interiors furnished with a pair of sealing rings, one which is lip-shaped, other convex shape, ensure dependable seal. With increasing water depth, rings experience augmented pressure, resulting gradual pressing in...