Coherent Precipitation and Strengthening in Compositionally Complex Alloys: A Review

Wang, Qing; Li, Zhen; Pang, Shujie; Li, Xiaona; Chen, Dong; Liaw, Peter K.

doi:10.3390/e20110878

“…The equilibrium shape of a precipitate is the result of balancing between the elastic strain energy and interfacial energy, which may influence magnetic behaviour 53 . The interfacial energy may be evaluated as a function of the coherent precipitate shape, L 54 : where ε is the lattice misfit between the particle and matrix, r is the particle size, and s is the interfacial energy. Via our experimental results, the mathematical relationships provide a way to use the equations as numerical laboratory to relate the relative changes in elastic strain energy and interfacial energy with magnetisation behaviour.…”

Section: Resultsmentioning

confidence: 99%

Magnetic properties of the complex concentrated alloy system CoFeNi0.5Cr0.5Alx

Morley

¹

,

Xi

²

,

Quintana-Nedelcos

³

et al. 2020

Sci Rep

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We study the change in magnetisation with paramagnetic Al addition in the CoFeNi 0.5 cr 0.5-Al x (x: 0, 0.5, 1, and 1.5) complex concentrated alloy. The compositions were developed utilising the Mulliken electronegativity and d-electron/atom ratio. Spherical FeCr rich nanoprecipitates are observed for X: 1.0 and 1.5 in an AlCoNi-rich matrix. A ~ 5 × increase in magnetisation (from 22 to 96 Am 2 /kg) coincides with this nanoprecipitate formation-the main magnetic contribution is determined to be from FeCr nanoprecipitates. The magnetisation increase is strange as paramagnetic Al addition dilutes the ferromagnetic Fe/Co/Ni additions. In this paper we discuss the magnetic and structural characterisation of the cofeni 0.5 cr 0.5-Al x composition and attempt to relate it to the interfacial energy. The innovation of new materials has been deemed to be the key topic for development of new technologies in our modern world. For alloys, the traditional approach has been to consider the effect of multiple dilute additions to a larger alloy matrix. New complex concentrated alloys (CCAs), which are near-equimolar multiple element alloys (> 3) challenge this view and have pushed alloy research towards the centre of phase diagrams 1,2. Multiple alloying components mean that they can possess large property permutations owing to the vast compositional space that they cover. Considerable work has been done on understanding how compositionalstructure affects mechanical properties. However, their functional properties are rarely the primary focus. As the base elements of CCAs are often CoFeNi (which is a known soft magnetic alloy), this can provide a basis for alloy design 1-5. Our motivation in this work is to therefore investigate the potential of CCAs as soft magnetic materials.

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“…( 2 –5) 64 – 69 : where M = 3.06 for FCC structure (Taylor factor) 68 , α ε = 2.6 (a constant) 66 , 67 , m = 0.85 (a constant) 70 , 71 , δ c = 2 δ /3 66 , 67 , the constrained lattice misfit. G = 81 GPa and ΔG = 4 GPa are the shear modulus of the matrix and the shear modulus misfit between precipitates and matrix, respectively 72 ; b = 0.254 nm is the Burgers vector 6 , 72 ; r is the average particle size (i.e., the average edge length of cuboidal precipitates measured from experimental observations) and f is the volume fraction of the γ′ precipitates, respectively; γ APB = 0.12 J/m 2 is the anti-phase boundary energy of γ′-Ni 3 Al 72 ; ν is the Poisson ratio ( ν = 0.35 for Ni-base superalloys 73 ), and λ p is the inter-precipitate space.…”

Section: Correlations Among Lattice Misfit Particle Morphology and mentioning

confidence: 99%

Composition rules of Ni-base single crystal superalloys and its influence on creep properties via a cluster formula approach

Chen

¹

,

Wang

²

,

Chen

³

et al. 2020

Sci Rep

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The present work investigated the composition evolution of the TMS series of Ni-base single crystal (SC) superalloys in light of the cluster formula approach systematically. The cluster formula of SC superalloys could be expressed with $${[}\overline{{{\text{Al}}}} {-} \overline{{{\text{Ni}}}} 12{](}\overline{{{\text{Al}}}} {, }\overline{{{\text{Cr}}}} {)}m$$ [ Al ¯ - Ni ¯ 12 ] ( Al ¯ , Cr ¯ ) m , in which all the alloying elements were classified into three groups, Al series ($$\overline{{{\text{Al}}}}$$ Al ¯ ), Cr series ($$\overline{{{\text{Cr}}}}$$ Cr ¯ ), and Ni series ($$\overline{{{\text{Ni}}}}$$ Ni ¯ ). It was found that the total atom number (Z) of the cluster formula units for TMS series of superalloys varies from Z ~ 17 to Z ~ 15.5, and then to Z ~ 16 with the alloy development from the 1st to the 6th generation, in which the superalloys with prominent creep resistance possess an ideal cluster formula of $${[}\overline{{{\text{Al}}}} {-} \overline{{{\text{Ni}}}} 12{](}\overline{{{\text{Al}}}} 1.5\overline{{{\text{Cr}}}} 1.5{)}$$ [ Al ¯ - Ni ¯ 12 ] ( Al ¯ 1.5 Cr ¯ 1.5 ) with Z = 16. Similar tendency of composition evolution also appears in the PWA and CMSX series of SC superalloys. Typical TMS series of superalloys with prominent creep properties generally exhibit a moderate lattice misfit of γ/γ′ which could render alloys with appropriate particle size of cuboidal γ′ precipitates to acquire a maximum strength increment by precipitation strengthening mechanism. More importantly, the relationship between the lattice misfit (δ) of γ/γ′ and the creep rupture lifetime (tr) of superalloys was then established, showing a linear correlation in the form of lgtr–lg|δ|3/2 at both conditions of 900 °C/392 MPa and 1100 °C/137 MPa. Combined with the lattice misfit, the cluster formula approach would provide a new way to modify or optimize the compositions of Ni-base superalloys for further improvement of creep property.

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“…Using the diameter of the precipitates 11±3 nm and the measured volume fraction 1.8%, the APB energy was estimated to be 183 mJ/m 2 and 123 mJ/m 2 at RT and 100 ºC, respectively. No literature data was found for the in β1′ (MgZn2), but a negative temperature dependence of the APB energy [150] has also been reported for Fe-Al [151] and Ni-Al [152,153] intemetallics.…”

Section: Precipitation Strengthening In the Crss For Basal Slip In Mgmentioning

confidence: 98%

High-throughput screening of strength and creep properties in Mg-Zn alloys

Li¹

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Looking back to the four years and three months that my Ph.D. journey took at IMDEA Materials Institute and the Polytechnic University of Madrid, I wish to express my sincerest and deepest gratitude to many people who offered me their support and help since the first day I arrived at IMDEA. First of all, I would like to express my most sincere gratitude to my supervisor Dr. Jon Molina. We did not even have a Skype meeting before and we only met after two months since I arrived at IMDEA. Thanks for your trust, for providing me with the opportunity to work in your group and for guiding me fully and patiently along this journey. At the beginning, I was new to the nanomechanical field, but you explained patiently the fundamental theory to me and checked the work carefully during each meeting. Gradually, you gave me a lot of freedom and your passion encouraged me to get deeper and deeper into the field. You helped me overcoming the difficulties and avoiding the mistakes that we often make when we work in a quick, eager and impetuous way, without deeper thinking. I still remember one day clearly, when you made me realize how natural aging at room temperature could influence the results on supersaturated Mg-Zn solid solutions. This made us introduce the topic of Zn distribution by studying the diffusion couple in the as-quenched, room aged and peak aged conditions. I also want to thank you for teaching me to think in a critical way, to improve my scientific writing and to help me differentiate between experimental evidence and mere speculation. Many thanks for all your wisdom guidance and continuous encouragement to help me grow during my study and work at IMDEA. Without your scholarly inputs and valuable guidance, this thesis would have not been possible. Your passion and solid background in materials science inspire me to continue working on materials research in the future. I feel so grateful and fortunate for having been working under your supervision and for growing up in our pleasant and exciting group. I also own my most sincere thanks to my other supervisor, Dr. Yuwen Cui, with whom I worked since I joined IMDEA Materials. Despite your departure one year later to Nanjing Tech University, you have remained deeply involved in my thesis. Your guidance, great patience and insightful vision was essential to introduce me in the field of high-throughput development of Mg alloys. I also wish to thank IMDEA Materials Institute for offering me such a fantastic environment for scientific research. I'm grateful for the financial support from the China Scholarship Council. My special thanks go to my colleagues: Dr. Miguel Monclus, thanks for your assistance with performing nanomechanical tests, which were always very timeconsuming; and Dr. Miguel Castillo, thanks for your help with the TEM characterizations and for training in the FIB. Special thanks to Dr. Lingwei Yang and Dr. Chuanyun Wang. You two taught and helped me a lot in micropillar testing and TEM lamellar preparation and also helped me analyse the data even during...

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Coherent Precipitation and Strengthening in Compositionally Complex Alloys: A Review

Cited by 122 publications

References 141 publications

Magnetic properties of the complex concentrated alloy system CoFeNi0.5Cr0.5Alx

Magnetic properties of the complex concentrated alloy system CoFeNi0.5Cr0.5Alx

Composition rules of Ni-base single crystal superalloys and its influence on creep properties via a cluster formula approach

High-throughput screening of strength and creep properties in Mg-Zn alloys

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