Large recoverable strain with suitable transition temperature in TiNb-based multicomponent shape memory alloys: First-principles calculations

Alloying Effect on Elastic and Mechanical Properties of Refractory Medium-Entropy Alloys from First-Principles Calculations

“…The random distribution of alloy atoms is described by CPA. , To ensure high accuracy of the results, we choose 19,000–27,000 uniformly distributed k points for elastic constants and 60,000–80,000 k points for DOS. The EMTO–CPA method has been successfully applied in studying elastic, mechanical properties, and phase transformation of Ti-based conventional alloys ,,− , and HEAs, ,, indicating that EMTO–CPA is a reliable method for designing complex alloys.…”

“…Debye temperature can be used to assess the effect of phonon vibrations, namely, increasing Debye temperature implies decreasing lattice vibration effects and vice versa. Thus, the composition dependence of elastic properties plays a key role in lattice dynamics, shear instability, phase stability, and energetics of nucleation associated with phase transformations. − Therefore, it is essential to describe and understand how elastic properties are affected by alloying elements. Alloying effect plays an important role in tuning the elastic and mechanical properties of alloys. − A systematic study of the alloying effect on RMEAs and RHEAs can provide a guidance for high-performance alloy design. − Owing to the complex component combination of RMEAs and RHEAs, so far there is still a big challenge to rapidly and precisely calculate their elastic moduli.…”

“…Revealing the relationship between mechanical properties and VEC is expected to provide a guideline for designing and screening high-performance RMEAs and RHEAs. Besides, the muffin-tin orbitals [exact muffin-tin orbital (EMTO)] method in combination with the coherent potential approximation (CPA) has been successfully applied to precisely calculate the elastic and mechanical properties of Ti-based conventional alloys ,,− and HEAs. ,− ,, …”

Metastability Engineering in Titanium Alloys Enables Advanced Structural/Functional Properties

“…Fine α precipitation renders high strength that is desirable for structural applications, [1,2] and β phase stability dependent reversibly thermoelastic martensitic transformation imparts unique functional properties including shape memory effect (SME) and superelasticity (SE). [3,4] Except for equilibrium α and β phases, the metastable ω phase, Oʹ phase, and martensite play a key role in microstructure evolution and mechanical properties of Ti alloys in either a direct or indirect way. Directly, they act as strengthening phases.…”

“…The transition of first-order martensitic transformation to nanodomain brings about novel functional properties, such as nearly hysteresis-free superelasticity [32] and superelasticity, invariant elastic modulus (Elinvar), and zero thermal expansion coefficient (Invar) over a wide temperature range. [3,[33][34][35] These unique properties originate from the occurrence of continuous and gradual structure transition from bodycentered cubic β phase to confined growth of orthorhombic nanodomain (Oʹ) without macroscopic phase transition, i.e., strain glass transition, over a wide temperature range. Based on the framework of strain glass theory, doping point defects like Zr, Sn, and interstitial oxygen and severe plastic deformation are beneficial for the successive formation of nanodomain in Ti alloys.…”