The effect of isotope on the dynamic behavior of 〈1 0 0〉 vacancy-type dislocation loop in deuterium-implanted Fe

• Vacancy-loop formed in D-implanted Fe after anneal at high temperature.
• V-loop formation temperature in D-implanted Fe is higher than that in H-implanted one.
• Dynamic behavior of 〈1 0 0〉 vacancy-loop in D-implanted Fe has been in situ observed.
• Growth and shrink rate of both type loops increase with increase of the damage rate.
• The origin for the behavior of both type loops was discussed in detail.

The dynamic behavior of individual loops of the both interstitial and vacancy types is believed to be strongly connected to the degradation processes that affect radiation-resistant materials used in nuclear-fission and fusion devices. Meanwhile, the isotopic effect of hydrogen on irradiation damage has attracted wide interest. In situ transmission electron microscopy investigation of the dynamic behavior of dislocation loops under high-energy electron irradiation was carried out in pure Fe with deuterium implantation at room temperature and aged at different temperatures. Shrinkage of dislocation loop was observed in implanted sample annealed at 753 K, except the popular growth of dislocation loop. The loop shrinkage was also observed in H implanted sample annealed at relatively lower temperature. The shrinking loop is identified to be 〈1 0 0 vacancy-type loop by acknowledged “inside–outside” method. Origin for the dynamic behavior of both type loops and the isotopic effect on the behavior were discussed.