@misc{LiangNeumeierRaoetal., author = {Liang, Zhida and Neumeier, Steffen and Rao, Ziyuan and G{\"o}ken, Mathias and Pyczak, Florian}, title = {CALPHAD informed design of multicomponent CoNiCr-based superalloys exhibiting large lattice misfit and high yield stress}, series = {Materials Science and Engineering: A, Structural materials}, volume = {854}, journal = {Materials Science and Engineering: A, Structural materials}, issn = {1873-4936}, doi = {10.1016/j.msea.2022.143798}, abstract = {Usually, Co-based superalloys contain a high fraction of W and/or Mo. The refractory elements stabilize the precipitate phase, but cause a high density. In this work, new L12-phase hardened, low-density CoNiCr-based superalloys were developed with the assistance of CALPHAD calculations. Several alloys were studied experimentally and their microstructures, elemental distributions, lattice parameters and the lattice misfit between the γ and γ′ phases were evaluated using scanning electron microscopy, transmission electron microscopy, atom probe tomography and high energy X-ray diffraction. The alloys exhibit a very high misfit, good phase stability and excellent mechanical strength. It was found by hardness tests that a two-step heat treatment improves the strength of the new alloys even further. In comparison with conventional Co-based superalloys, Co-Al-W based superalloys and Co-Ti based superalloys, as well as Ni-based superalloys, i.e. Udimet 720Li, they have a low mass density and high yield stress. They also overcome the problem of a generally low lattice misfit of previous L12-phase hardened CoNiCr-based superalloys with high Ni and Cr contents. As a result, they show cuboidal-shaped precipitates similar to Co-Al-W and Co-Al-Mo based superalloys.}, language = {en} } @misc{PyczakLiangNeumeieretal., author = {Pyczak, Florian and Liang, Zhida and Neumeier, Steffen and Rao, Ziyuan}, title = {Stability and Physical Properties of the L12-γ′ Phase in the CoNiAlTi-System}, series = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science}, volume = {54}, journal = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science}, number = {5}, issn = {1073-5623}, doi = {10.1007/s11661-022-06949-y}, pages = {1661 -- 1670}, language = {en} }