Sharif Digital Repository

A modified method of severe plastic defomation (SPD) entitled constrained groove pressing-cross route (CGP-CR) was introduced for imposing a high magnitude of equivalent strain of about 2.32 per pass on the sheet form samples. The major benefit of this improved route compared to previous common route was the more homogeneity of strain in the rolling (RD) and transverse (TD) directions of sheets. In this study, low carbon steel samples were used for examination of evolutions in microstructure and mechanical properties during SPD via CGP-CR process. Mechanical properties improvement were measured by tensile and macro hardness tests. The results indicate that CGP-CR process can effectively... 

In this work, the 6061 aluminum alloy tubes are severely deformed through a novel method called Tube Channel Pressing (TCP). The ability of this process in improving mechanical properties, grain refinement and microstructural changes of the alloy with different heat treatments before and after TCP process is investigated. Results show that TCP has notable effect on grain refinement and decreases crystallite size of solid solution treated aluminum 6061 material to 52. nm after equivalent strain of 3.09 which is comparable with the measured data from other SPD processes. The strength of the specimens aged before TCP is higher than that of those aged after TCP. The specimens artificially aged... 

A new severe plastic deformation (SPD) method entitled Tube Channel Pressing (TCP) is proposed. In this study, the ability of TCP on strength improvement and grain refinement is assessed. This method is based on pressing a tube through a tubular channel die with a neck zone. Utilization of a mandrel fitted inside the tube prevents the crumpling of tube and preserves its initial dimension. Due to the symmetric design, after one pass, the die is rotated upside down and the second pass is applied by pressing the tube in inverse direction. Ultimate strength of a commercial purity aluminum tube after 5 successful passes is improved to 2 times of the initial strength. Analytical calculations and...