Search

Ta/Re layered composite material is a high-temperature material composed of the refractory metal tantalum (Ta) as the matrix and high-melting-point, high-strength rhenium (Re) as the reinforcement layer. It holds significant potential for application in aerospace engine nozzles. Developing the Ta/Re potential function is crucial for understanding the diffusion behavior at the Ta/Re interface and elucidating the high-temperature strengthening and toughening mechanism of Ta/Re layered composites. In this paper, the embedded atom method (EAM) potential function for tantalum/rhenium binary alloys (Ta-Re alloys) is derived using the force-matching method and validated through first-principles calculations and experimental characterization. The results show that for the lattice constant of a bcc structure containing 54 atoms, surface formation energies per unit area of Ta-Re alloys obtained based on the potential function are 12.196 Å, E100 = 0.16 × 10−2 eV, E110 = 0.10 × 10−2 eV, and E111 = 0.08 × 10−2 eV, with error values of 0.015 Å, 0.04 × 10−2 eV, 0.02 × 10−2 eV, and 0.01 × 10−2 eV, respectively, compared with the calculations from first principles calculations. It is noteworthy that the errors in the average binding energies of Ta-rich (Ta39Re20, where the number of Ta atoms is 39 and Re atoms is 20) and Re-rich (Ta20Re39, where the number of Ta atoms is 20 and Re atoms is 39) cluster atoms, calculated by the potential function and first-principles methods, are only 1.64% to 1.98%. These results demonstrate the accuracy of the constructed EAM potential function. Based on this, three compositions of Ta-Re alloys (Ta48Re6, Ta30Re24, and Ta6Re48; the numerical subscripts represent the number of atoms of each corresponding element) were randomly synthesized, and a comparative analysis of their bulk moduli was conducted. The results revealed that the experimental values of the bulk modulus showed a decreasing and then an increasing tendency with the calculated values, which indicated that the potential function has a very good generalization ability. This study can provide theoretical guidance for the modulation of Ta/Re laminate composite properties. [ABSTRACT FROM AUTHOR]

In many critical biological processes, host-guest chemistry of protein receptors is regulated by effector molecules to realize cascaded delivery of messenger molecules between different targets. Mimicking these natural processes with artificial receptors remains a challenge. Herein, we report a cascaded guest delivery between two anionocages (anion-coordination-driven cages), in a reversible manner, wherein binding of K + ions by a crown ether functionalized, heteroleptic A 2 L 3 (A=anion, L=ligand) anionocage triggers the release and delivery of a TEA + (tetraethylammonium) guest to another A 2 L 3 anionocage that is a weaker and less K + -sensitive receptor. Elimination of the K + with [2,2,2]-cryptand enables recapture of the TEA + by the crown ether functionalized anionocage and thus realizes a reversed guest delivery. Moreover, integrative self-sorting of anionocages is firstly reported, leading to heteroleptic cages with enhanced guest binding affinities., (© 2021 Wiley-VCH GmbH.)