Lonardelli, Ivan (2010) Deformation mechanisms in bulk nanostructured aluminum obtained after cryomilling and consolidation by spark plasma sintering. PhD thesis, University of Trento.
|PDF - Doctoral Thesis|
Bimodal bulk nanocristalline (nc)/ultrafine (UF) aluminum was produced after cryomilling and spark plasma sintering consolidation process. The samples obtainedwere plastically deformed in uniaxial compression. We show that there is a significant fraction of plastic strain (11%) that can be recovered after unloading. High-energy synchrotron X-ray diffraction experiments revealed that, there is a correlation between plastic strain recovery and microstructural evolution detected during in-situ loading-unloading experiments. Using a deconvolution approach, the nanostructured volume fraction (grain size below 100 nm) and the UF counterpart (grain size above 100-150 nm)were separated in terms of lattice strain, microstrain, crystallite size and crystallographic texture. During loading-unloading cycles we observe a lattice strain splitting between nc and UF volume fractions, a complete recovery of the peak broadening and a recovery of texture. These intriguing phenomena were explained to be strictly correlated with the lattice strain splitting behavior which act as the driving force for dislocation recombination.
|Item Type:||Doctoral Thesis (PhD)|
|Doctoral School:||Materials Engineering (till the a.y. 2009-10, 25th cycle)|
|Subjects:||Area 09 - Ingegneria industriale e dell'informazione > ING-IND/21 METALLURGIA|
|Repository Staff approval on:||07 Jun 2010 09:18|
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