ISSN:
1013-9826
Quelle:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Thema:
Maschinenbau
Notizen:
In the present paper, in order to better understand the third type “dynamic strainaging” occurring during the plastic flow of metals, the uniaxial compressive experimentaldata ever obtained in University of California, San Diego using an Instron servo-hydraulictesting machine and the Hopkinson technique are systematically analysed. These experimentaldata cover the plastic flow stress of several fcc, hcp, bcc polycrystalline materials and severalalloys at a broad range of temperatures (77K – 1,100K) and strain rates (0.001/s – 10,000/s).In analysis, the appearing region of the “dynamic strain aging ” under different temperaturesand strain rates are respectively plotted by the curves of stress vs temperature, and stress vsstrain for fcc, hcp and bcc metals. The results show that: (1) this third type “dynamic strainaging ” occurs in all hcp, bcc and fcc polycrystalline or alloy materials, and there are differentprofiles of stress-strain curve; (2) the “dynamic strain aging ”occurs in a matchingcoincidence of the temperature and strain rate, its temperature region will shift to higherregion with increasing strain rates; (3) bcc materials do not have an initial pre-straining strainas the onset of work-hardness rate change for the “dynamic strain aging ”; and (4) based onthe explanations of dynamic strain aging with serration curves (Portevin-Lechatelier effect)and other explaining mechanisms of references, The mechanism of third DSA is thought asthe rapid/continuous formation of the solute atmospheres at the mobile dislocation core by thepipe diffusion along vast collective forest dislocations to result in a continuous rise curve offlow stress. Finally, several conclusions are also presented
Materialart:
Digitale Medien
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.340-341.823.pdf
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