Abstract
The alloying effects of Ni,W and Cr on the microstructural stability of CoNi-base alloys were investigated using a multicomponent diffusion multiple after being aged at 1000 ℃ for 1000 h.The diffusion multiple was carefully designed based on thermodynamic calculations.The relationships between alloy compo-sitions and microstructural characteristics were established over a large compositional range using this single sample,and the alloying effects of Ni,W and Cr on the elemental partitioning behaviors between γ and γ'two phases were thermodynamically analyzed using high-throughput calculation.The results together show that an increase of Ni content increases the γ'volume faction in the long-term aged microstructures.However,the higher Ni content leads to the precipitation of the x phase by promoting the partitioning of W from the γ'phase to the γphase.The decrease of W content dramatically reduces the γ'volume faction,but the addition of Cr can properly counteract this effect by promoting the partitioning of Al and Ti from the γphase to the γ'phase.This study will be helpful for accelerating the development of novel γ'-strengthened multicomponent CoNi-base alloys,as well as providing experimental data to improve the thermodynamic database.
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