Defect structure development in electron irradiated Cu-Pd and Cu-Pt alloyswith 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 int eractions and their effects on defect structure development. This paper rep orts 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 G e (about +30%), and they belong to the same group as Ni (an undersize solut e) in the periodic table of elements. At lower temperatures, the addition o f 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 als o voids between 373 It and 523 It. 0.3 at.% of Pd or Pt, however, did not i nduce 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-poi nt defect interactions are not characterized only by atomic volume size fac tor.