Diffusivities and Atomic Mobilities in bcc Ti-Mo-Zr Alloys.

Weimin Bai,Lijun Zeng,Zhijie Yang,Libin Liu,Mingyue Tan,Guanglong Xu,Ligang Zhang,Di Wu

doi:10.3390/ma11101909

Weimin Bai, Lijun Zeng + Show 6 more

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https://doi.org/10.3390/ma11101909

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Abstract

β-type (with bcc structure) titanium alloys have been widely used as artificial implants in the medical field due to their favorable properties. Among them, Ti-Mo alloy attracted numerous interests as metallic biomaterials. Understanding of kinetic characteristics of Ti alloys is critical to understand and manipulate the phase transformation and microstructure evolution during homogenization and precipitation. In this work, diffusion couple technique was employed to investigate the diffusion behaviors in bcc Ti-Mo-Zr alloys. The diffusion couples were prepared and annealed at 1373 K for 72 h and 1473 K for 48 h, respectively. The composition-distance profiles were obtained via electron probe micro-analysis (EPMA). The chemical diffusion coefficients and impurity diffusion coefficients were extracted via the Whittle-Green method and Hall method. The obtained diffusion coefficients were assessed to develop a self-consistent atomic mobility database of bcc phase in Ti-Mo-Zr system. The calculated diffusion coefficients were compared with the experimental results. They showed good agreement. Simulations were implemented by Dictra Module in Thermo-Calc software. The predicted composition-distance profiles, inter-diffusion flux, and diffusion paths are consistent with experimental data, confirming the accuracy of the database.

Highlights

Due to their biocompatibility, low modulus, high specific strength, and high corrosion resistance, β-type and near β titanium alloys have been widely used as surgery implants [1,2,3,4]
There is no Kirkendal void existing in the diffusion zone and no microstructure presented in
There is no Kirkendal void existing in the diffusion zone and no evident, revealing that the alloys were annealed in single bcc phase

Summary

Introduction

Low modulus, high specific strength, and high corrosion resistance, β-type (with bcc structure) and near β titanium alloys have been widely used as surgery implants [1,2,3,4]. Previous studies have verified that Nb, Zr, Mo, Hf, and Ta are effective alloying elements leading to low elastic modulus, nontoxic, and non-allergic β-Ti alloys [4,5,6]. Mo is a strong β-phase stabilizing element for titanium alloys and the Ti-Mo based alloys exhibit adequate mechanical compatibility and good cyto-compatibility [9,10,11,12]. The Ti-Mo-Zr system, which showed good performances and magnificent prospects in biomaterial application, has been intensively studied [3,6,10,11,12,13]. Several alloys related to the Ti-Mo-Zr system have been investigated recently, for example, Ti-12Mo-6Zr-2Fe [14], Ti-15Mo-5Zr-3Al [15], and Ti-8Mo-4Nb-2Zr [6]

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