Synergistic effect of rhenium and ruthenium in nickel-based single-crystal superalloys

Effect of Re on lattice trapping in γ′-Ni3Al cracks by atomistic simulation

“…The lower value of the average binding energy indicates that Re atom prefers to occupy the corresponding site. Apparently, it can be seen from Table 2 that Re atom preferentially occupies the Al site, which is in agreement with the previous theoretical and experimental studies [21,25,33,34]. Thus, Re atoms substitutes for Al sites in all the doped systems in the present study.…”

“…While, the strengthening mechanism of Ni-based SC superalloys due to the addition of Re is not fully understood. It was proved that Re mainly partitions into the c 0 phase in ternary alloy [20,21]; and a certain number of Re atoms partition into the c 0 phase in multi-component superalloys [22][23][24]. At present, the strengthening mechanism of Re doped in c 0 -Ni 3 Al was properly investigated by the first-principles approach [25][26][27][28].…”

Influence of Ru on creep behaviour and concentration distribution of Re-containing Ni-based single crystal superalloy at high temperature

“…What's more, the content of Re in γ' phase of Re/Ru-containing alloy after crept is reduced to 0.33 at.% from 0.63 at.%, the distribution ratio of the one in γ'/γ phases reduces from 1/5.02 to 1/10.75, while the concentration and ratio of other elements do not significantly change. After added Ru element, some of Ru atoms may substitute for Al atom in Ni 3 Al phase [13], and the Ru atoms possess a stronger binding energy with Re, W and Mo atoms because of the hybridization and interaction of their d-electron layers [15], which may depress the diffusion of Re, W atoms around Ru during creep. Therefore, the Ru, Re, W in γ, γ' phases keeps the stable concentration.…”

“…But for Re/Ru alloy after crept until rupture, the reason of more KW locks retaining in γ' phase is put down to the interactivity of Ru and Re, W. The Ru may replace the Al atoms in γ'-Ni 3 Al phase. The interactivity of the Ru and Re, W atoms [15] enhances their bonding energy, so that more Re, W atoms are reserved in γ' precipitates to enhance alloying extent, which can depress the diffusion of elements and gliding of dislocations, so more KW locks are reserved in γ' precipitates of Re/Ru alloy after crept until rupture at 1100°C/137 MPa. Hence, compared with Re alloy, the Re/Ru alloy exhibits a better creep property owing to more KW locks maintaining in γ' phase to depress the dislocations gliding.…”

Influence of withdrawal rate on last stage solidification path of a Mo-rich Ni3Al based single crystal superalloy

“…Nowadays, in order to further improve the high temperature properties of Ni based SC superalloys, refractory elements (such as Re, W, Mo and Ta) are increasingly added in SC superalloys, which causes severe microsegregation and numerous interdendritic precipitation during solidification, leading to the increment of difficulty of solution treatment [4][5][6]. Therefore the solidification path and interdendritic precipitation have been widely studied in CMSX-4 [7], CMSX-10 [7], CMSX-10K [8][9][10], Astra series alloys [11], CM and UM series alloys [12], etc.…”