Achieving excellent strength-ductility-superelasticity combination in high-porosity NiTiNb scaffolds via high-temperature annealing

Document Type

Journal Article

Publication Title

Journal of Materials Science and Technology

Volume

206

First Page

221

Last Page

233

Publisher

Elsevier

School

Centre for Advanced Materials and Manufacturing / School of Engineering

RAS ID

71334

Funders

National Natural Science Foundation of China

Grant Number

52274387, 52311530772

Comments

Liu, W., Zhang, Y., Wang, B., Liu, S., Wang, Y., Zhang, L., ... & Wang, L. (2025). Achieving excellent strength-ductility-superelasticity combination in high-porosity NiTiNb scaffolds via high-temperature annealing. Journal of Materials Science & Technology, 206, 221-233. https://doi.org/10.1016/j.jmst.2024.03.064

Abstract

Metallic scaffolds with lightweight, low elastic modulus, and high energy-absorbing capacity are widely utilized in industrial applications but usually require post-heat treatment to enhance their comprehensive mechanical properties. However, it is unclear how to utilize the impact of β-Nb on the surrounding matrix for NiTiNb ternary alloys to achieve strength-ductility-superelasticity enhancement. Here, we prepared rhomboidal dodecahedral NiTiNb porous scaffolds with a porosity of 85.9% by additive manufacturing. Subsequently, annealing treatment was employed to drastically reduce the phase transformation temperatures and expand the thermal hysteresis. Interestingly, the 850 °C annealed scaffold exhibited exceeding double compressive strength of the as-built sample, with a remarkable improvement in ductility and superelasticity. From the microstructure perspective, high-temperature annealing caused a further eutectic reaction of the unmelted Nb particles with the NiTi matrix and the transformation of mesh-like β-Nb into dispersedly distributed spherical β-Nb particles. The microstructure evolution after deformation indicated that stress-induced martensitic transformation occurred in the matrix away from the NiTi-Nb eutectic region whereas almost no martensite formed nearby β-Nb particles. Atom probe tomography characterization revealed an element diffusion zone in several nanometers surrounding the β-Nb particle, where the substitution of Nb with Ti led to a higher Ni: Ti atomic ratio, lowering transformation temperatures. Molecular dynamics simulations illustrated that β-Nb particles can not only entangle dislocations internally, acting as reinforcements but also hinder the twin growth, contributing to strain hardening. This work elucidates the influence of β-Nb particles on the deformation mechanism of the NiTi-Nb eutectic region through in-depth atomic-scale investigation, which can provide inspiration for the improvement of comprehensive mechanical properties of NiTiNb alloys.

DOI

10.1016/j.jmst.2024.03.064

Access Rights

subscription content

Link to Full Text

Share

 
COinS