A fundamental understanding of the interactions between point defects and grain boundaries (GBs) is critical to designing radiationtolerant nanocrystalline (nc) materials. An important consideration in this design is sink strength, which quantifies the efficiency of a sink to annihilate point defects. Contrary to the common belief that random high-angle GBs provide the upper limit for rate of defect annihilation, here we show that the sink strength of low-angle GBs can exceed that of high-angle GBs due to the effect of GB stress fields. This surprising finding provides a novel opportunity to enhance the radiation resistance of nc materials through GB engineering. © 2013 The Author(s). Published by Taylor & Francis.

Narasimhan Swaminathan

Department of Mechanical Engineering

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Effect of Grain Boundary Stresses on Sink Strength

Materials Research Letters

Using a rate theory model for a generic one-component material, we investigated interactions between grain size and recombination kinetics of radiation-induced defects. Specifically, by varying parametrically nondimensional kinetic barriers for defect diffusion and recombination, we determined the effect of these parameters on the shape of the dose to amorphization versus temperature curves. We found that whether grain refinement to the nanometer regime improves or deteriorates radiation resistance of a material depends on the barriers to defect migration and recombination, as well as on the temperature for the intended use of the material. We show that the effects of recombination barriers and of grain refinement can be coupled to each other to produce a phenomenon of interstitial starvation. In interstitial starvation, a significant number of interstitials annihilate at the grain boundary, leaving behind unrecombined vacancies, which in turn amorphize the material. The same rate theory model with material-specific parameters was used to predict the grain-size dependence of the critical amorphization temperature in SiC. Parameters for the SiC model were taken from ab initio calculations. We find that the fine-grained SiC has a lower radiation resistance when compared to the polycrystalline SiC due to the presence of high-energy barrier for recombination of carbon Frenkel pairs and due to the interstitial starvation phenomenon. © 2012 American Physical Society.

Physical Review B - Condensed Matter and Materials Physics

Role of recombination kinetics and grain size in radiation-induced amorphization

Functional Materials Letters

Author Index Volume 7 (2014)

Acta Materialia

Size dependence of radiation-induced amorphization and recrystallization of synthetic nanostructured CePO4 monazite

Effect of grain boundary character on sink efficiency

Nano Letters

Are Nanoporous Materials Radiation Resistant?

Effect of grain boundary stresses on sink strength

Journal	Materials Research Letters
Publisher	Taylor \& Francis
ISSN	21663831
Open Access	No