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:
In situ tensile tests were conducted on ultra fine grained (UFG) pure Pd and Pd-x% Ag(x=20, 60) alloys of different stacking fault energies (SFEs) with the aim to study the generalfeatures of the deformation process of UFG materials as well as the peculiarities brought by thealloying. Grey scale correlation analysis (GSCA) was used to determine the true strain as well asthe surface flow within the gauge length. It was shown that the largest values of strength anduniform elongation were obtained in Pd-20% Ag alloy. The GSCA revealed different macroscopicflow processes in this sample as compared with pure Pd and Pd-60% Ag alloy. In particular, purePd and Pd-60% Ag alloy demonstrated rapid localization of plastic flow in the neck area, whereasPd-20% Ag samples showed a large contribution of homogenous deformation even after neckformation. It has been proposed that larger strain hardening capacity of Pd-20% Ag alloy is relatedto its lower SFE as compared with that of pure Pd: the lower is the SFE, the more difficult is thecross slip and climb of split dislocations, which leads to enhanced dislocation storage and,ultimately, to increased strain hardening. At the same time, further decrease of SFE in Pd-60% Agsample leads to development of deformation twinning and consequent reduction of strain hardening.The dimpled structure of fracture surfaces in the samples will also be discussed in relationship tothese findings
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.584-586.249.pdf
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