Efficient Coarse‐Grained Superplasticity of a Gigapascal Lightweight Refractory Medium Entropy Alloy

Abstract

Superplastic metals that exhibit exceptional ductility (>300%) are appealing for use in high‐quality engineering components with complex shapes. However, the wide application of most superplastic alloys has been constrained due to their poor strength, the relatively long superplastic deformation period, and the complex and high‐cost grain refinement processes. Here these issues are addressed by the coarse‐grained superplasticity of high‐strength lightweight medium entropy alloy (Ti43.3V28Zr14Nb14Mo0.7, at.%) with a microstructure of ultrafine particles embedded in the body‐centered‐cubic matrix. The results demonstrate that the alloy reached a high coarse‐grained superplasticity greater than ≈440% at a high strain rate of 10−2 s−1 at 1173 K and with a gigapascal residual strength. A consecutively triggered deformation mechanism that sequences of dislocation slip, dynamic recrystallization, and grain boundary sliding in such alloy differs from conventional grain‐boundary sliding in fine‐grained materials. The present results open a pathway for highly efficient superplastic forming, broaden superplastic materials to the high‐strength field, and guide the development of new alloys.

Mapping current high-entropy materials for water electrolysis: from noble metal to transition metal

“…[72][73][74][75] High-entropy materials include highentropy alloys, high-entropy oxides, high-entropy hydroxides, high-entropy phosphides and other subgroups. [76][77][78] The interactions between uniformly mixed metal atoms modulate their electronic structures and optimize the ability to adsorb and desorb intermediates, enabling the use of high entropy materials in a wide range of catalytic applications.…”

“…In HEMs, the diffusion rate of atoms is much slower than that of low entropy alloy or single-component materials. 77 This is due to the interaction between different atoms and lattice distortion in high entropy alloys, which seriously affects the effective diffusion rate of atoms. Phase transition requires synergistic diffusion between the primary elements to achieve phase separation equilibrium; thus, the hysteresis diffusion effect will affect the formation of new phases in high entropy alloys, favoring high entropy alloys as stable catalysts.…”

Grain Distribution for Optimal Strength in Homogeneous and Gradient Nano‐Grained Coppers

“…[17,41] Subsequently, some subgrains undergo grain rotation, which increase the orientation difference between adjacent grains. [42] Finally, these subgrains nucleate and grow into new small grains. The data in Table 1 show that the GB percentage growth rates during plastic deformation are positive for both structures, but are higher for the random structure.…”

Theoretical insights into the lattice thermal conductivity and thermal expansion of CoNiFe medium-entropy alloys

“…Medium-entropy alloys (MEAs) [1][2][3] have been attracting the attention of researchers due to their excellent mechanical properties, [4][5][6][7][8] especially the alloy systems based on Al and the fourth row elements Fe, Co, Ni, Cr, Cu, Mn and Ti, and Pd. [9][10][11][12][13][14][15] For example, Lang et al 14 studied and compared the formation and evolution of irradiation-induced defects in CoNiFe alloys and pure Ni using molecular dynamics (MD) simulations.…”