Researchers using Argonne’s Intermediate Voltage Electron Microscope (IVEM) are exploring deliberate introduction of nanovoids in conjunction with nanotwins to enable unprecedented damage tolerance in metallic materials.
Material performance in extreme radiation environments is central to the design of future nuclear reactors. Radiation induces significant damage in the form of dislocation loops and voids in irradiated materials, and continuous radiation often leads to void growth and subsequent void swelling in metals with low stacking fault energy.
Here we show that by using in situ heavy ion irradiation in a transmission electron microscope, pre-introduced nanovoids in nanotwinned Cu efficiently absorb radiation-induced defects accompanied by gradual elimination of nanovoids, enhancing radiation tolerance of Cu. In situ studies and atomistic simulations reveal that such remarkable self-healing capability stems from high density of coherent and incoherent twin boundaries that rapidly capture and transport point defects and dislocation loops to nanovoids, which act as storage bins for interstitial loops.
Y. Chen, K.Y. Yu, Y. Liu, S. Shao, H. Wang, M. A. Kirk, J. Wang and X. Zhang, “Damage-tolerant Nanotwinned Metals with Nanovoids Under Radiation Environments,” Nature Communications 6, Article Number: 7036. DOI: 10.1038/ncomms8036, Published April 24, 2015.