title: Radiation-Induced Helium Nanobubbles Enhance Ductility in Submicron-Sized Single-Crystalline Copper.
abstract: The workability and ductility of metals usually degrade with exposure to irradiation, hence the phrase "radiation damage". Here, we found that helium (He) radiation can actually enhance the room-temperature deformability of submicron-sized copper. In particular, Cu single crystals with diameter of 100-300 nm and containing numerous pressurized sub-10 nm He bubbles become stronger, more stable in plastic flow and ductile in tension, compared to fully dense samples of the same dimensions that tend to display plastic instability (strain bursts). The sub-10 nm He bubbles are seen to be dislocation sources as well as shearable obstacles, which promote dislocation storage and reduce dislocation mean free path, thus contributing to more homogeneous and stable plasticity. Failure happens abruptly only after significant bubble coalescence. The current findings can be explained in light of Weibull statistics of failure and the beneficial effects of bubbles on plasticity. These results shed light on plasticity and damage developments in metals and could open new avenues for making mechanically robust nano- and microstructures by ion beam processing and He bubble engineering.
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale & Hysitron Applied Research Center in China, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University , Xi'an 710049, P.R. China.
authors.forename: Ming-Shuai
authors.initials: MS
authors.lastname: Ding
authors.affiliation: Department of Mechanical Engineering and Bioengineering, Osaka University , Osaka 565-0871, Japan.
authors.forename: Jun-Ping
authors.initials: JP
authors.lastname: Du
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale & Hysitron Applied Research Center in China, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University , Xi'an 710049, P.R. China.|Department of Mechanical Engineering and Bioengineering, Osaka University , Osaka 565-0871, Japan.
authors.forename: Liang
authors.initials: L
authors.lastname: Wan
authors.affiliation: Department of Mechanical Engineering and Bioengineering, Osaka University , Osaka 565-0871, Japan.|Center for Elements Strategy Initiative for Structural Materials, Kyoto University , Kyoto 606-8501, Japan.
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Ogata
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale & Hysitron Applied Research Center in China, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University , Xi'an 710049, P.R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Tian
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale & Hysitron Applied Research Center in China, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University , Xi'an 710049, P.R. China.|Department of Materials Science and Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States.
authors.forename: Evan
authors.initials: E
authors.lastname: Ma
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale & Hysitron Applied Research Center in China, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University , Xi'an 710049, P.R. China.
authors.forename: Wei-Zhong
authors.initials: WZ
authors.lastname: Han
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale & Hysitron Applied Research Center in China, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University , Xi'an 710049, P.R. China.|Department of Nuclear Science and Engineering and Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Ju
authors.initials: J
authors.lastname: Li
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale & Hysitron Applied Research Center in China, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University , Xi'an 710049, P.R. China.
authors.forename: Zhi-Wei
authors.initials: ZW
authors.lastname: Shan
keywords: He bubble; Radiation damage; ductility; in situ TEM; submicron-sized