An ab initio Investigation of the Mechanical and Electronic properties of High Strength, Ceramics and Multi-Layered Thin Films

In recent times material design has become an important part of materials research. In particular, the design and subsequent fabrication of materials for specific high strength applications is of great interest. The aim of this project is to examine the mechanical and electronic properties of ceramics (such as Si3N4, SiAlON, SiC, BN, etc.) and multi- layered thin films (such as TiC/TiN/C3N4 layered films). Specifically, ab initio modelling will be used to characterise the link between impurity doping and crystal structure in ceramics, and the interlayer bonding characteristics of various thin films. Ultimately, the understanding gained will add to the knowledge base of material design techniques.

Principal Investigator

Cenk Kocer
School of Physics
University of Sydney

Project

h63

RFCD Codes

240202

Significant Achievements, Anticipated Outcomes and Future Work

Using the well known ab initio software package, VASP, I have studied groups of materials that exhibit good potential in the application of high strength, high temperature applications. Initial calculations were performed to characterize bulk material behavior of the Silicon Nitride and Boron Nitride systems. The results have added to the knowledge base of these materials. These calculations are finished and I am now looking at a new group of materials. I have been doing the,

Structural optimization of a new group of rare earth SiAlON composite materials and binary nitrides (such as Al-X, X=Ir, Co, Ga, N, ..) Calculation of the Mechanical Properties of these systems, elastic constants, bulk modulus, shear modulus and hardness Calculation of the electronic properties of these systems, Charge distribution, density of states and the band structure Calculation of phase transformation and enthalpy energetics

These calculations are ongoing and the availability of VASP on the APAC system has meant a significant reduction (in the case of my work) in the calculation time for obtaining accurate results. I hope to continue these calculations and contribute to the understanding of material properties in these systems. Results of data obtained from these calculations have been published.

 

Data Sources, Curation Techniques, Data Access Policy and Method

None

 

Computational Techniques Used

I use the VASP ab initio software package. The density functional approach is well suited for the structural optimisation of atomic level structures and the estimation of material properties, such as elastic properties. No modifications are applied and the code is used in a standard manner.

The package is used to find the stable atomic configuration of crystal structures. This structure is then used to calculate the mechanical and electronic response.

 

Publications, Awards and External Funding

External Funding and Awards

None.

Publications

References of work containing data calculated using the APAC system.
'Ab initio characterization of the mechanical and electronic properties of SiAlON (Si6–zAlzOzN8–z; z=0–5)' N. Hirosaki, C. Kocer, S. Ogata and K. Tatsumi Phys. Rev. B, 71, (2005) 104105-104117

'Thermodynamic Assessment of the Al-Ir System' T.Abe, M.Ode, H.Murakami, C.S.Oh, C.Kocer, and H.Onodera Current Advance in Materials and Process, 18 [6], (2005) 1272-1276

'The strength and hardness of cubic spinel SiAlON' C. Kocer, N. Hirosaki and S. Ogata Acta Scripta., in press 2006