Mechanical response of mesoporous amorphous NiTi alloy to external deformations

Abstract

The porous titanium nickelide is very popular in various industries due to unique combination of physical and mechanical properties such as shape memory effect, high corrosion resistance, and biocompatibility. The non-equilibrium molecular dynamics simulation was applied to study the influence of porosity degree on mechanical properties of porous amorphous titanium nickelide at uniaxial tension, uniaxial compression, and uniform shear. We have found that the porous amorphous alloy is characterized by a relatively large value of Young's modulus in comparison to its crystalline analogue. It has been found that the system with a percolated network of pores exhibits improved elastic characteristics associated with resistance to tensile and shear. The system contained isolated spherical pores is more resistant to compression and less resistant to tensile and shear. These results can be applied to develop and improve the methods for making amorphous metal foams.

Structural Change of TiAl Alloy under Uniaxial Tension and Compression in the <001> Direction: A Molecular Dynamics Study

“…The same conclusion was reported by Galimzyanov and Mokshin [46], who carried out a computational study to investigate the effect of porosity on the mechanical properties of NiTi alloys. Through shear, tensile, and compression tests, it can be concluded that the increasing porosity of NiTi alloys causes a decrease in the modulus of elasticity and strength of the NiTi alloy [46]. Similar studies may need to be carried out on TiAl alloys to inspire potential wider applications in the future.…”

“…However, they are stiffer under tensile loading than under compression. In the case of compressive testing for systems with porosity, the compressive strength decreases in materials with greater porosity, as was the result of a previous study by Xu et al [45] and Galimzyanov and Mokshin [46] for the NiTi alloy system. [21]; c from ref.…”

“…Xu et al [45] reported that the higher the porosity of the material, the lower the compressive strength and modulus of elasticity of the material, which indicates that the mechanical properties of the NiTi alloy biomaterial can be adjusted to the supported bone by tuning the porosity of the material [45]. The same conclusion was reported by Galimzyanov and Mokshin [46], who carried out a computational study to investigate the effect of porosity on the mechanical properties of NiTi alloys. Through shear, tensile, and compression tests, it can be concluded that the increasing porosity of NiTi alloys causes a decrease in the modulus of elasticity and strength of the NiTi alloy [46].…”

“…One of the interesting topics to be studied in the future is the effect of porosity on the mechanical properties of TiAl alloys. In the research results that have been reported recently, the mechanical properties of the NiTi alloy biomaterial were affected by the porosity of the material [46]. Xu et al [45] reported that the higher the porosity of the material, the lower the compressive strength and modulus of elasticity of the material, which indicates that the mechanical properties of the NiTi alloy biomaterial can be adjusted to the supported bone by tuning the porosity of the material [45].…”

Structural transformations in binary Ni62Nb38 alloy at ultrahigh temperatures

“…Figure 1 (see inset) shows the T-dependence of the fraction of liquid phase atoms with respect to the atoms of the entire system. The form of this dependence is typical for activation-type processes, such as the crystal nucleation and the formation of liquid droplets in saturated vapor [17][18][19][20], and this dependence is well reproduced by the exponential expression of the following form…”