Positron lifetime study of dislocations in metals

正电子寿命测量已经在一些面心立方金属和合金上进行，这些金属和合金被处理成在这样的特定条件下，只主要包含给定类型的位错。结果表明，正电子寿命随位错Burgers矢量的大小单调增加。当位错实际上是扩展的，观察到的正电子寿命来自部分位错，是显着短于在未解离的位错。目前的研究结果不仅表明，正电子湮没参数主要来自位错线本身，但也表明，正电子寿命谱可以用来区分不同类型的位错。

Positron lifetime measurements have been performed on some fcc metals and alloys, which were treated to be in such specific conditions that only a given type of dislocations are predominantly contained. The results show that the positron lifetime increases monotonously with the magnitude of Burgers vectors of dislocations. When dislocations are actually extended, the observed positron lifetime comes from partial dislocations and is remarkably shorter than that at undissociated dislocations. Present results not only demonstrate that positron annihilation parameters observed predominantly come from dislocation lines themselves but also show that positron lifetime spectroscopy can be used to differentiate between different types of dislocations.