|Support type:||Scholarships in Brazil - Master|
|Effective date (Start):||March 01, 2014|
|Effective date (End):||July 31, 2015|
|Field of knowledge:||Engineering - Materials and Metallurgical Engineering - Physical Metallurgy|
|Principal Investigator:||Claudio Shyinti Kiminami|
|Grantee:||Francisco Gil Coury|
|Home Institution:||Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil|
Classically, high strength aluminum alloys have been developed based on the mechanisms of solidsolution hardening, precipitation, grain refining, work hardening and through composites by dispersing particles and fibers in an aluminum matrix. Based on these mechanisms strength resistance has been limited to about 500-600 MPa at room temperature. More recently, new aluminum alloys containing metastable phases (non-equilibrium) such as amorphous phases, nanocrystalline and nanoquasicrystalline have been developed. With such microstructures containing amorphous or crystalline matrix and dispersions of nanoparticles with amorphous, crystalline or nanocrystalline structure, strength up to 1 GPa have been achieved. Particularly Al alloys with icosahedral phases (quasicrystals QC) already have several industrial applications. The first paper concerning Al alloys with QC phases reported their formation in thin ribbons with micrometric thickness, solidified under very high cooling rates, around 106 K/s. Since the practical use of melt-spun ribbons for mechanical applications is obviously limited, there have been a number of investigations to produce such Al-based alloys with QC phases in form of bulk samples. It is vital to understand the mechanisms of formation of QC phases from the molten state and the influence of the chemical composition in order to be able to control the microstructural changes reaching the situation where the QC phases are formed primarily under controllable dimensions. In this context, this dissertation project proposes to study the mechanisms of formation of quasicrystalline phases in aluminum alloys at low cooling rates from the liquid.