Simulation of Nucleation and Growth of GP-Zones in Al-Cu-Alloys

• Applicant: Professor Dr. Günter Gottstein
• Subject Area: Synthesis and Properties of Functional Materials
• Term: from 2002 to 2007
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5397425

The joint project involves studying phase structure and phase transformation of alloys by a combination technique of first-principles quantum theory calculation with statistical mechanics method. Multi-scale modeling phase transformations and microstructure evolution of solids is a promising research field and is showing its increasing importance for materials design by computation. By combining first-principles techniques with statistical mechanics methods, researcher opens the possibility of exploring, without any fitting parameters, thermodynamics phenomena such as phase transformation temperatures, phase diagrams, short-range order, anti-phase and interphase boundary energetics etc. Age-hardening by precipitation is one of the most important mechanisms for strengthening of Al-alloys. In the proposed project we focus on the early stages of precipitation, i.e. on the nucleation and growth of Guinier and Preston (GP) zones. It is expected that the results of this study will significantly promote our understanding of nucleation mechanism of the precipitation process. Furthermore, this approach based on physical parameters will be helpful for addressing other alloys, and to transfer the obtained results for modeling of nucleation in models working on coarser scales. A very interesting approach for understanding formation of GP-zones and metastable phases in more detail. After earlier work on simulation of GP-zone formation in the Gottstein group now a combination technique of first principles quantum theory calculation with statistical mechanics methods will be developed. Such an approach should open the possibility of exploring thermodynamics phenomena without any fitting parameter. The use of quantum theory calculations should allow for example to calculate the bonding energy of formation of the disc-shaped GP-zones and to study the strain In my opinion this is a very exciting proposal, even despite some unclear use of terms like metastable or stable phases as well as zones which are usually not assumed as Since very large experimental results are already available on the formation of GP-zones (for example detailed X-ray analysis by Gerold), only a few additional metallographic investigations might be The cost calculations, in particular for personnel costs for the German side, are rather Very good proposal which might belong to the highest 2. "Sy stem/Theory: GP-Zones in Al-Cu, computer Fits in the concept: Originality: Expected result: Quality: Quality of the German applicants: Quality of the oral presentation in Beijing: Recommendation: take into Detailed remarks: Despite the criticism in Beijing the interactioas defined a of them resgrowth of thi Der Gutachter befürwortet die Förderung des Vorhabens.

• DFG Programme: Research Grants