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:
The effect of interpass time during thermomechanical processing of AA61111 on flowbehaviour and microstructure evolution has been investigated. This was achieved using plane straincompression testing undertaken on the Sheffield thermomechanical compression (TMC) facility,using the hit-hold-hit-quench approach. Following solution treatment at 560°C for 1200s, sampleswere water mist quenched to 320°C and deformed at a constant strain rate of 85s-1 to an initial strainof 0.5, unloaded and held for delay times of 0.019, 6, 60, 600 and 6000s and then given a seconddeformation for a further strain of 0.5, followed by a water quench to room temperature. Hardeningof the alloy was observed, the extent of which was dependent on the hold time. The microstructureof the samples was quantified by TEM in order to determine the extent of strain inducedprecipitation. TEM identified precipitation, predominantly β and Q phases, on dislocation lines, thesize and volume fraction of which were a function of the hold time. The coarsening rate during thehold period of the precipitates was considerably faster than for coarsening following a conventionalprecipitation treatment. The size of the microband structure at the end of the double deformationwas a function of the hold time, suggesting that coarsening of the precipitates during the hold hadaltered the Zener pinning potential. The implication of these observations on the thermomechanicalprocessing of 6xxx alloys is discussed
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/16/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.550.211.pdf
Permalink
