Atomistic characterization of chemical element distribution is crucial to understanding the role of alloying elements for strengthening mechanism of superalloy. In the present work, the site preferences of two alloying elements X-Y in γ-Ni of Ni-based superalloy are systematically studied using first-principles calculations with and without spin-polarization. The doping elements X and Y are chosen from the 27 kinds of 3d, 4d, 5d group transition metals (Sc,
Using high-throughput first-principles calculations, we systematically studied the synergistic effect of alloying two elements (Al and 28 kinds of 3d, 4d, and 5d transition metals) on the elastic constants and elastic moduli of γ-Ni. We used machine learning to theoretically predict the relationship between alloying concentration and mechanical properties, giving the binding energy between the two elements. We found that the ternary alloying elements strengthened the γ phase in the order of Re > Ir > W > Ru > Cr > Mo > Pt > Ta > Co. There is a quadratic parabolic relationship between the number of d shell electrons in the alloying element and the bulk modulus, and the maximum bulk modulus appears when the d shell is half full. We found a linear relationship between bulk modulus and alloying concentration over a certain alloying range. Using linear regression, we found the linear fit concentration coefficient of 29 elements. Using machine learning to theoretically predict the bulk modulus and lattice constants of Ni 32 XY , we predicted values close to the calculated results, with a regression parameter of R 2 = 0.99626. Compared with pure Ni, the alloyed Ni has higher bulk modulus B, G, E, C 11 , and C 44 , but equal C 12 . The alloying strengthening in some of these systems is closely tied to the binding of elements, indicating that the binding energy of the alloy is a way to assess its elastic properties.
In this study, the precipitation and hardening of a commercial 6061 Al alloy during the combined natural and artificial ageing are analyzed, in order to maximize the alloy hardness by adjusting ageing time and temperature. The samples were solution-treated at 540°C for 2 hours, followed by water quenching. An artificial ageing was performed at 180, 200, and 220°C during a period from 2 min to 12 h. Natural ageing at room temperature during 12 h was performed simultaneously with the artificial one at different elevated temperatures. The Vickers hardness values of solution-treated and aged samples were measured. Precipitates were characterized via the X-ray diffraction and scanning transmission electron microscopy equipped with the energy dispersive X-ray spectroscopy. The highest hardness values were exhibited by samples that were naturally aged for 12 hours and artificially aged for 24 hours at 200 and 220°C. The hardness improvement was found to be controlled by the formation of β” phases before the peak ageing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.