Bulk nanostructured materials by large strain extrusion machining

2007 ◽  
Vol 22 (1) ◽  
pp. 201-205 ◽  
Author(s):  
W. Moscoso ◽  
M.R. Shankar ◽  
J.B. Mann ◽  
W.D. Compton ◽  
S. Chandrasekar

Large strain extrusion machining (LSEM) is presented as a method of severe plastic deformation for the creation of bulk nanostructured materials. This method combines inherent advantages afforded by large strain deformation in chip formation by machining, with simultaneous dimensional control of extrusion in a single step of deformation. Bulk nanostructured materials in the form of foils, plates, and bars of controlled dimensions are shown to result by appropriately controlling the geometric parameters of the deformation in large strain extrusion machining.

2015 ◽  
Vol 1114 ◽  
pp. 143-148
Author(s):  
Nicolae Serban ◽  
Doina Răducanu ◽  
Vasile Danut Cojocaru ◽  
Nicolae Ghiban

Severe plastic deformation (SPD) has received enormous interest over the last two decades as a method capable of producing fully dense and bulk ultra-fine grained (UFG) and nanocrystalline (NC) materials. Significant grain refinement obtained by SPD leads to improvement of mechanical, microstructural and physical properties. Compared to classical deformation processes, the big advantage of SPD manufacturing techniques, represented in particular by equal channel angular pressing (ECAP) is the lack of shape-change deformation and the consequent possibility to impart extremely large strain. In ECAP processing, the workpiece is pressed through a die in which two channels of equal cross-section intersect at an angle of ϕ and an additional angle of ψ define the arc of curvature at the outer point of intersection of the two channels. As a result of pressing, the sample theoretically deforms by simple shear and retains the same cross-sectional area to allow repeated pressings for several cycles. A commercial AlMgSi alloy was investigated in our study. The specimens were processed at room temperature for multiple passes, using three different ECAP dies. All samples (ECAP processed and as-received) were subjected to metallographic analysis and mechanical testing. Several correlations between the main processing parameters and the resulting microstructural aspect and mechanical features for the processed material were established. It was shown that severe plastic deformation by means of ECAP processing can be used in aluminum alloys microstructural design as an advanced tool for grain refinement in order to attain the desired microstructure and mechanical properties.


2006 ◽  
Vol 114 ◽  
pp. 7-18 ◽  
Author(s):  
Ruslan Valiev

During the last decade severe plastic deformation (SPD) has become a widely known method of materials processing used for fabrication of ultrafine-grained materials with attractive properties. Nowadays SPD processing is rapidly developing and is on the verge of a transition from lab-scale research to commercial production. This paper focuses on several new trends in the development of SPD techniques for effective grain refinement, including those for commercial alloys and presents new SPD processing routes to produce bulk nanocrystalline materials.


2008 ◽  
Vol 584-586 ◽  
pp. 9-15 ◽  
Author(s):  
Tasha Reshetnikova ◽  
Milyausha R. Salakhova ◽  
Zarema A. Safargalina ◽  
Andrey V. Shcherbakov

This report presents main achievements of international R&D activities of the Institute of Physics of Advanced Materials of Ufa State Aviation Technical University (Ufa, Russia) with a special attention to the innovative potential of nanostructured metals and alloys produced by severe plastic deformation techniques. Several examples of the first promising applications of bulk nanostructured materials as well as potential competing technologies are considered and discussed.


2000 ◽  
Vol 45 (2) ◽  
pp. 103-189 ◽  
Author(s):  
R.Z Valiev ◽  
R.K Islamgaliev ◽  
I.V Alexandrov

2007 ◽  
Vol 539-543 ◽  
pp. 2787-2792 ◽  
Author(s):  
Minoru Umemoto ◽  
Yoshikazu Todaka ◽  
Jin Guo Li ◽  
Koichi Tsuchiya

Formation of nanocrystalline structure by severe plastic deformation has studied extensively. Although ultra fine grained structure (grain size larger than 100 nm) had been obtained in many processes such as heavy cold rolling, equal channel angular pressing (ECAP) or accumulative roll bonding (ARB), the formation of nano grained structure (< 100 nm) is limited to processes such as ball milling, shot peening or drilling. In the present study, high pressure torsion (HPT) deformation and drilling were carried out to understand the conditions necessary to obtain nano grained structure in steels. The results of HPT experiments in pure Fe showed that HPT has superior ability of strengthening and grain refinement probably due to a strain gradient but the saturation of grain refinement occurs before reaching nano grained structure. Drilling experiments in high carbon martensitic steel revelaed that nano grained ferrite forms at the drilled hole surface only when the transformation from ferrite to austenite takes place during drilling. Considering various other processes by which nano grained ferrite was produced, it is proposed that heavy strains with large strain gradients together with dynamic transformation are necessary to reach nano grained ferrite structure.


2018 ◽  
Vol 33 (22) ◽  
pp. 3762-3773
Author(s):  
Sepideh Abolghasem ◽  
Saurabh Basu ◽  
Shashank Shekhar ◽  
M. Ravi Shankar

Abstract


2006 ◽  
Vol 503-504 ◽  
pp. 639-644 ◽  
Author(s):  
Vanessa Vidal ◽  
Ludovic Thilly ◽  
Florence Lecouturier

Nanofilamentary wires consisting of a Cu matrix reinforced by body centred cubic (bcc) nanofilaments were produced by successive hot extrusion and large strain drawing. Effects of this severe plastic deformation on the microstructure and the mechanical properties of two systems, Cu/Ta and Cu/Nb/Cu “co-cylindrical” structure, are presented and compared with the nanofilamentary Cu/Nb wires.


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