Deformation mechanisms in bulk nanostructured aluminum obtained after cryomilling and consolidation by spark plasma sintering

Lonardelli, Ivan (2010) Deformation mechanisms in bulk nanostructured aluminum obtained after cryomilling and consolidation by spark plasma sintering. PhD thesis, University of Trento.

[img]
Preview
PDF - Doctoral Thesis
5Mb

Abstract

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)
PhD Cycle:XXII
Subjects:Area 09 - Ingegneria industriale e dell'informazione > ING-IND/21 METALLURGIA
Repository Staff approval on:07 Jun 2010 09:18

Repository Staff Only: item control page