SHI SHI

Quantitative analysis of the impact of the compositional complexity in a series of Ni-containing concentrated solid-solution alloys, Ni, NiCo, NiFe, NiCoCr, NiCoFeCr, NiCoFeCrMn and NiCoFeCrPd, on the evolution of defects produced by 1?MeV Kr ion irradiation at 773?K is reported. The dynamics of the evolution of the damage structure during irradiation to a dose of 2 displacements per atom were observed directly by performing the ion irradiations in electron transparent foils in a transmission electron microscope coupled to an ion accelerator. The defect evolution was assessed through measurement of the defect density, defect size and fraction of perfect and Frank loops. These three parameters were dependent on the alloying element as well as the number of elements. The population of loops was sensitive to the ion dose and alloy composition as faulted Frank loops were observed to unfault to perfect loops with increasing ion dose. These dependences are explained in terms of the influence of each element on the lifetime of the displacement cascade as well as on defect formation and migration energies.

One-dimensional glide of loops during ion irradiation at 773 K in a series of Ni-containing concentrated solid solution alloys has been observed directly during experiments conducted inside a transmission electron microscope. It was found that the frequency of the oscillatory motion of the loop, the loop glide velocity as well as the loop jump distance were dependent on the composition of the alloy and the size of the loop. Loop glide was most common for small loops and occurred more frequently in the less complex alloys, being highest in Ni, then NiCo, NiFe and NiCoFeCr. No measurable loop glide occurred in the NiCoCr, NiCoFeCrMn and NiCoFeCrPd alloys.