Defect structure development in electron irradiated Cu-Pd and Cu-Pt alloys with HVEM

Copper base binary alloys have been irradiated with 1 MeV electrons using a high-voltage electron microscope in order to study solute-point defect interactions and their effects on defect structure development. This paper reports results on Cu-Pd and Cu-Pt, and compares them with previous results on Cu-Ni, -Si, -Ge, and -Sn. Pd and Pt have a similar volume size factor as Ge (about +30%), and they belong to the same group as Ni (an undersize solute) in the periodic table of elements. At lower temperatures, the addition of Pd and Pt was found to stabilize interstitial-type dislocation loops, but did not increase the loop number density as drastically as the addition of Si, Ge, or Sn. Addition of 2 at.% of Pd or Pt resulted in the formation of stacking fault tetrahedra (SFTs) stable up to higher temperatures, and also voids between 373 K and 523 K. 0.3 at.% of Pd or Pt, however, did not induce either stable SFTs or voids. In contrast, addition of 0.3 at.% Si, Ge, and Sn was found to stabilize SFTs. These results suggest that solute-point defect interactions are not characterized only by atomic volume size factor.