ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Annealed pure copper was subjected to equal-channel angular pressing (ECAP) by routeBc for different passes number. Tensile test specimens were manufactured and subjected to hardcyclic viscoplastic (HCV) deformation by means of the materials testing installation Instron 8516 instrain control regime at room temperature. The specimens were cyclically deformed with afrequency of 0.5Hz at different strain amplitudes, step-by-step increased from ±0.05 to ±2.5% for30 cycles, up to seven test series in this study.The microstructure of ECAP and HCV deformed samples were characterized by optical- andtransmission electron microscope, X-ray diffraction, tensile- and hardness testing methods.The ECAP processed metal has mainly elongated subgrains with low-angle grain boundaries andtexture, oriented in direction of metal flow during latest pressing. We demonstrate that during HCVdeformation the dislocations density of ECAP processed UFG copper was decreased. The ECAPtexture was reoriented under cyclic load applied as elongated subgrains were jointed to small piecesunder this same angle to axis as texture before. The grain- and crystallite sizes were decreased,which were accompanied with dislocation ribbons forming nearby new formed high-angle grainboundaries. This paper builds on knowledge that the combined treatment by ECAP and followedHCV deformation enable to improve UFG microstructure and ductility with lowering the strengthand hardness of UFG metals due to the lower dislocation density while coarse grained copperexhibits increasing the strength and hardness
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.584-586.361.pdf
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