Bulk Nanomaterials and Powders Consolidation Produced by Cyclic Extrusion Compression

Abstract

The Cyclic Extrusion – Compression - reciprocating extrusion process (CEC) is one of severe plastic deformation methods (SPD), which allow to produce bulk nanomaterials without changing the initial shape of deformed samples. The results are presented showing that the average grains size and microbands thickness in aluminium alloys decrease below 100 nm. The investigations revealed that the average grains size is about 250 nm and 200 nm in polycrystalline and monocrystalline copper, respectively.The Cyclic Extrusion Compression method is also used to produce bulk materials by powder consolidation. The subgrains/nanograins inside the silver powder particles after the consolidation processes achieved the mean size of about 100 nm. Moreover, it has been found that inside structure observed by TEM, the consolidated powder granules consisted from nanometric twins of about 10 – 20 nm. This silver based powder consolidated by CEC method were extruded by hydrostatic extrusion method. The final product were the wires with a diameter of 3 mm, which were used to electrical contacts production.

Deformation Microstructures in Metallic Materials after Severe Plastic Deformation by Rolling with Cyclic Movement of Rolls

“…Obtained results are in accordance with literature [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Enhanced mobility of dislocations in Al and Cu due to the lack of alloying elements to hinder the dislocation movement results in weakening of grain refinement.…”

“…RCMR with a strain (ε f t ) of about ≈7 shows similar results as the CEC with a strain of ≈5 in Al refinement. In AlMg5 alloy after deformation about ≈14, the mean width of the microbands was 156 nm [13]. In our experiment the average value of grains/subgrain size in AlMg5 alloy were about twice lower but the strain was twice smaller, too (Fig.…”

“…The second group of non-ferrous materials, which play a key role in electric engineering are copper and copper alloys. In literature the effectiveness of SPD methods has been revealed for a pure Al [7][8][9][10][11][12][13], Al-Mg alloys [13,14], pure Cu [11,[13][14][15][16][17][18][19] and Cu-Fe [20] alloys. Recent works have demonstrated [21,22] that one of the method which can be used for SPD processing is rolling with cyclic movements of rolls (RCMR).…”

Effect of Continuous RCS Deformation on Microstructure and Properties of Copper and Copper Alloys Strips

“…Many well know methods of Severe Plastic Deformation (SPD) of metals are used for refinement of microstructure of metals and alloys. The most popular SPD methods include High-Pressure Torsion (HPT) [1], Equal Channel Angular Pressing (ECAP) [2,3], Cyclic Extrusion-Compression (CEC) [4,5], Multiaxial Forging (MF), Accumulative Roll-Bonding (ARB) [6], Hydrostatic Extrusion (HE) [7], GP techniques [8], Repetitive Corrugation and Straightening (RCS) [9][10][11].…”

Analysis of Microstructure and Mechanical Properties Changes in AA1050 Aluminum Subjected to ECAP and KoBo Processes / Analiza Zmian Mikrostruktury I Własności Mechanicznych Aluminium AA1050 Po Procesie ECAP I KoBo

“…Worth noting is the fact that processes of severe plastic deformation may be applied using combination of the various methods. Few of the most relevant are high pressure torsion HPT [11,12], twist extrusion TE [13,14], accumulative rollbonding ARB [15,16], cyclic extrusion compression CEC [17]. Relatively new and promising one is a KoBo method.…”