Nanostructuring of Cu-TiB2 induced by ion irradiation

Lokesh, Rannesh

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https://hdl.handle.net/2142/24007 Copy

Description

Title

Nanostructuring of Cu-TiB2 induced by ion irradiation

Author(s)

Lokesh, Rannesh

Issue Date

2011-05-25T14:50:44Z

Director of Research (if dissertation) or Advisor (if thesis)

• Bellon, Pascal
• Averback, Robert S.

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Copper alloys
• nanostructure
• transmission electron microscopy
• precipitation

Abstract

The stability of materials under irradiation is a critical topic and has been an area of fundamental interest in particular for materials used in nuclear reactors. These dissipative systems which exist far from equilibrium pose a challenge in understanding due to the existence of multiple dynamical processes, which are often competing. Recent modeling and experimental results of Cu-base alloys indicate that these dynamical processes can lead to nanostructuring in binary alloy system. Nanostructuring at steady state under irradiation could result in materials with very high irradiation resistance as interfaces can trap point defects and He atoms. The objective of this work was to study whether nanostructuring could also take place in multicomponent systems, possible involving the precipitation of compounds. The Cu-TiB2 alloy system was selected and microstructural evolutions induced by 1.8 MeV Kr ion irradiation with varying fluence and wide range of temperatures were investigated. An additional objective was to identify the mode of formation of these nanostructures. Homogeneous co-sputtered Cu-TiB2 films as well as Cu/TiB2 multilayers were grown by physical vapor deposition as starting materials. Transmission electron microscopy revealed that irradiation of initially homogeneous films led to the nanoscale precipitation of second phase TiB2 particles, with an average diameter of 5 nm. This nanostructuring reached similar steady states for irradiation temperatures ranging from room temperature to 650 °C. It is thus concluded that this nanoprecipitation takes place in displacement cascades.

Graduation Semester

2011-05

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http://hdl.handle.net/2142/24007

Copyright and License Information

Copyright 2011 Rannesh Lokesh

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