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 this study, susceptibility to SCC of nanostructured Cu-10wt%Zn alloys, produced byequal-channel angular pressing (ECAP) was investigated under the constant stress test in ammoniavapour, which has been well-known typical environment for IGSCC of Cu-Zn alloy. Billets havingdiameter of 20 mm and length of 100 mm were subjected to ECAP for eight passes at roomtemperature to obtain structure with grain size of about 100 nm. After ECAP, some of the billets wereflush-annealed in 473 K for 60 seconds to decrease excessive unequilibrium dislocations at grainboundaries. Coarse grained specimens without ECAP and one-pass specimens were also tested forcomparison. The specimens for SCC were tensioned by a constant load in ammonia vapour inside aglass chamber for 24 hours at room temperature. After the SCC tests, maximum length of cracks wasevaluated by SEM. Specimen having UFG structure by 8-passes exhibited cracks in lower appliedstress ratio, (=σa/σys) compared with 0- and 1-pass samples, where σa is applied stress and σys is yieldstress, respectively. Most importantly, the specimen with annealed at 473K for 60s after ECAPcracked in higher applied stress. It became less sensitive to SCC after flush annealing althoughmechanical properties were not changed considerably. In our previous studies, we reported that theSCC of UFG copper produced by ECAP, and the sensitivity to SCC becomes lower by flush annealing.Results are discussed in terms of grain boundary state with or without extrinsic grain boundarydislocations
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.584-586.887.pdf
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