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:
Equal channel angular extrusion (ECAE), involving intense plastic straining under highapplied pressure is generally recognized and extensively studied top down approach for producingbulk ultra-fine grained (UFG) metallic materials, and even going down in size to the nanometerrange. In this research efforts are made to identify conditional under which grains with size lessthan 100 nm form after ECAE. Evolution of microstructure of Al-Li based alloy processed byECAE is analyzed using transmission electron microscopy (TEM). Observations on the effect ofprecipitates/second phase particles in the sample on the deformation characteristics and their role onthe increased degree of grain fragmentation process is highlighted. Samples of Al-Li based alloyare solutionized, quenched and aged at different temperatures to obtain well formed precipitatelaths/plates before subjecting to ECAE. During the deformation process these precipitatesdisintegrate into fragments and get dispersed into the Al matrix. The fragments of a fewnanometers size bring about drastic changes in the flow as well as the recovery characteristics ofprocessed samples. Evidence for dynamic recrystallisation taking place during the ECAEprocessing is presented. It was observed that optimal thermal treatment leads to more effectivegrain refinement and consequently an ultra-fine grained microstructure could be achieved even aftersingle pass in Al-Li based alloy containing precipitates and second phase particles
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.584-586.411.pdf
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