A study of Re and Al diffusion in Ni

Influence of withdrawal rate on the microstructure of Ni-base single-crystal superalloys containing Re and Ru

“…The obviously reduced segregation can be detected when withdrawal rate greater than 100 m/s. The segregation of Re and W are difficult to be eliminated even by the complicated solution heat treatments [7,20]. Therefore, the greatly refined dendritic structures with low degree of segregation are beneficial for reducing the time for heat treatments and improving the mechanical properties.…”

Influence of Aluminum and Rhenium on the Isothermal Oxidation Behavior of CoNiCrAlY Alloys

“…Similar study in a Ni-based superalloy CMSX-5 has also shown an influence of Re on the diffusion behavior of alloying elements, particularly that of Al, to the surface [31]. Limited diffusion data demonstrated that at 1000°C the diffusion coefficient of Al in c-Ni with 3 wt% Re was 4.38 9 10 -11 cm -2 s -1 [32], but in Re-free c-Ni was 1.2 9 10 -11 cm -2 s -1 [33]. EDS results obtained in the present work (Tables 6, 7) revealed that Al-rich oxides in the Re-containing alloys prevailed over that found on Re-free alloys, which strongly indicate that the addition of Re favored a higher flux of Al to the oxidizing surface, resulting in an accelerated formation of a complete, purer Al 2 O 3 layer with less Co, Ni containing spinels, like NiAl 2 O 4 .…”

Hot Corrosion of Ti–Re Alloys Fabricated by Selective Laser Melting

“…Even during hot corrosion tests of Ti-47Al-1Re-1W-0.2Si (at.%) at 750-800°C for longer times, rhenium outward diffusion was not observed [37]. Rhenium is a very heavy slow-diffusing element [38] as shown by Zeng et al [39] and Zhang et al [40] for nickel and nickel-based superalloys. Therefore, the observed phenomenon has to be associated with the presence of undissolved Re particles at this particular location.…”