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CN-121976152-A - Zinc-doped fine-grain titanium alloy with high corrosion-resistant self-repairing passivation film and preparation method thereof

CN121976152ACN 121976152 ACN121976152 ACN 121976152ACN-121976152-A

Abstract

The invention provides a zinc-doped fine-grain titanium alloy with a high corrosion-resistant self-repairing passivation film and a preparation method thereof, and belongs to the technical field of titanium alloy materials. The method comprises the steps of processing grooves on the surface of a Ti-35Nb-2Ta-3Zr alloy matrix, filling zinc powder, adopting friction stir processing to process the Ti-35Nb-2Ta-3Zr alloy matrix filled with the zinc powder under the protection of inert gas, and carrying out in-situ mechanical alloying to enable zinc element to be in solid solution into the Ti alloy matrix, and meanwhile refining crystal grains to form a fine crystal structure and inhibit omega phase generation. According to the invention, zinc element is doped in situ in the stirring friction processing process of the Ti-35Nb-2Ta-3Zr alloy, a solute-defect cooperative regulation mechanism is constructed, omega phase generation is inhibited while the strength of crystal grains is improved, and the self-repairing of the passivation film is realized by utilizing processing defects. The technology solves the contradiction between plastic deformation strengthening and corrosion resistance of the traditional titanium alloy, realizes uniform solid solution distribution of zinc element, and remarkably improves the long-term corrosion resistance stability of the titanium alloy in physiological environment.

Inventors

  • WANG LIQIANG
  • CUI YUWEI
  • JIANG DEYU

Assignees

  • 上海交通大学

Dates

Publication Date
20260505
Application Date
20260203

Claims (8)

  1. 1. The preparation method of the zinc-doped fine-grain titanium alloy with the high corrosion-resistant self-repairing passivation film is characterized by comprising the following steps of: step (1), processing grooves on the surface of a Ti-35Nb-2Ta-3Zr alloy matrix and filling zinc powder; under the protection of inert gas, adopting friction stir processing to treat a Ti-35Nb-2Ta-3Zr alloy matrix filled with zinc powder, enabling zinc element to be in solid solution into the titanium alloy matrix through in-situ mechanical alloying, and refining crystal grains to form a fine crystal structure and inhibiting omega phase generation; wherein, the technological parameters of friction stir processing are that the rotation speed of a cutter is 200 revolutions per minute, the transverse moving speed is 50 mm per minute, and the pressing depth is 0.2-0.4 mm.
  2. 2. The method for preparing a zinc-doped fine-grain titanium alloy with a highly corrosion-resistant self-repairing passivation film according to claim 1, wherein in the step (2), a cutter used for stirring friction processing has a conical probe and flat shoulder structure, wherein the length of the conical probe needle is 1.7 mm, the diameter of the root is 5.0 mm, the diameter of the tip is 3.0 mm, and the diameter of the flat shoulder is 12 mm.
  3. 3. The method for producing a zinc-doped fine-grain titanium alloy with a highly corrosion-resistant self-repairing passivation film according to claim 1, wherein in the step (1), the Ti-35Nb-2Ta-3Zr alloy matrix is produced by arc melting, and the melting process is performed in a high-purity argon atmosphere.
  4. 4. The method for preparing the zinc-doped fine-grain titanium alloy with the high corrosion-resistant self-repairing passivation film according to claim 1, wherein in the step (2), the fine-grain structure is formed by severe plastic deformation generated by friction stir processing, and grain boundaries and dislocations introduced during grain refinement serve as solute diffusion channels, so that the passivation film is rapidly repaired.
  5. 5. The method for preparing a zinc-doped fine-grain titanium alloy with a highly corrosion-resistant self-repairing passivation film according to claim 1, wherein the purity of zinc powder is not less than 99.9%, and the granularity is nano-scale.
  6. 6. The method for preparing a zinc-doped fine-grain titanium alloy with a highly corrosion-resistant self-repairing passivation film according to claim 5, wherein the grain size of the zinc powder is 50nm.
  7. 7. The method of any one of claims 1 to 6, wherein in step (2), the inert gas is argon.
  8. 8. A zinc-doped fine-grain titanium alloy with a highly corrosion-resistant self-repairing passivation film, characterized in that it is prepared by the preparation method of any one of claims 1 to 7, and the alloy structure has no ω phase.

Description

Zinc-doped fine-grain titanium alloy with high corrosion-resistant self-repairing passivation film and preparation method thereof Technical Field The invention relates to the technical field of titanium alloy materials, in particular to a zinc-doped fine-grain titanium alloy with a high corrosion-resistant self-repairing passivation film and a preparation method thereof. Background Titanium and titanium alloys are widely used in aerospace and medical implant fields because of their excellent specific strength, corrosion resistance and biocompatibility. In recent years, with the increase of requirements on mechanical matching and service safety of implant materials, beta titanium alloys with low elastic modulus are becoming research hot spots. By regulating and controlling the alloy components and the structure, the alloy has good chemical stability while ensuring high strength, and is an important direction for the development of the current titanium alloy materials. In the prior researches, fine-grain strengthening is considered to be one of effective ways for improving the comprehensive performance of the titanium alloy. Friction stir processing (Friction Stir Processing, FSP), which is a solid state severe plastic deformation technique, can significantly refine grains without melting to obtain a uniform equiaxed recrystallized structure, and thus is widely used for surface or local structure modification of titanium alloys. However, the means of severe plastic deformation such as FSP introduces fine-grain structure, and at the same time, high-density dislocation, subgrain boundary and residual stress are inevitably generated, so that unbalanced phase transformation (such as ω phase) is easily induced, thereby adversely affecting electrochemical stability of the material. In a physiological corrosive environment, this microscopic electrochemical heterogeneity may accelerate the occurrence of localized corrosion. In order to further improve the service performance of the titanium alloy in physiological environments, researchers try to introduce elements with bioactivity or antibacterial performance such as Zn, ag and the like into the titanium alloy so as to improve the corrosion resistance and the biological function of the material in an alloying way. Currently, the existing surface modification scheme is the ultrasonic surface rolling technique (Ultrasonic Surface Rolling Process, USRP). The technology drives the balls/rollers to impact and squeeze the metal surface through high-frequency ultrasonic vibration, so that the surface layer generates severe plastic deformation, and the superfine crystal layer, high residual compressive stress and extremely low surface roughness are obtained. The main characteristics of ultrasonic rolling technology in the treatment of titanium alloys include: physical strengthening, namely, the dislocation is greatly proliferated and rearranged through cyclic impact, surface layer grains are thinned to nano-scale, and the hardness and fatigue resistance are obviously improved. The surface integrity has peak clipping and valley filling effects, can obviously reduce the surface roughness and provides an extremely flat processing surface. The corrosion resistance is influenced by the fact that the refined grain boundary increases the atomic diffusion flux, and the passivation film can be accelerated to form under certain environments. Although the ultrasonic rolling technology has remarkable effect in mechanical strengthening, the ultrasonic rolling generally only changes the physical morphology and structure of the surface layer of the material, and the precise depth distribution and in-situ alloying of functional alloy elements (such as Zn element with antibacterial and solid solution stabilizing effects) in the modified layer are difficult to realize. In the ultrasound roll-pressed structure, high density dislocations and grain boundaries exist mainly as energy traps, increasing the gibbs free energy of the system. The prior art fails to convert these "detrimental" defects into "favorable" channels that promote migration of active solute atoms and repair of membrane defects. The prior art has the following defects: (1) There is an inherent contradiction between severe plastic deformation strengthening and corrosion resistance The existing titanium alloy with refined grains realized by a serious plastic deformation method such as Friction Stir Processing (FSP) and the like can introduce a large number of unbalanced defects (high-density dislocation and subgrain boundary) and stress induced phases (such as omega phase) while improving the strength, so that the electrochemical non-uniformity of the surface of the material is obviously enhanced, and the corrosion preferential growth area is formed. (2) The traditional alloying mode is difficult to consider the effective utilization of fine grain structure and active elements When active elements such as Zn are added in a smeltin