CN115463965B - A gradient micro-nanostructured Ti-TiZnX layered composite material and preparation method thereof - Google Patents

Abstract

The invention relates to the field of material processing, in particular to a gradient micro-nano structure Ti-TiZn _X layered composite material and a preparation method thereof, comprising the following steps: cutting pure titanium sheets and pure zinc sheets into the same size, cleaning the surfaces, sequentially stacking at intervals, and fixing to obtain laminated sheets; subjecting the obtained laminated sheet to clad-rolling treatment: firstly hot rolling at a certain temperature, and then cold rolling to realize the preliminary combination of pure titanium and pure zinc sheets, thus obtaining a pure titanium-pure zinc combined sample; and performing diffusion heat treatment on the rolled pure titanium-pure zinc combined sample at a certain temperature to form gradient micro-nano structures of TiZn ₃ and TiZn _X compounds in a zinc layer area in the middle of adjacent pure titanium sheets, thus obtaining the Ti-TiZn _X layered composite material with the gradient micro-nano structure. The pure titanium matrix of the composite layer prepared by the invention has strong binding force with the compound layer, a composite region of titanium zinc element is formed between the pure titanium layers, and the components and tissues in the composite region are distributed in a gradient way.

Description

A gradient micro-nanostructured Ti-TiZnX layered composite material and preparation method thereof

Technical Field

The invention relates to the field of material processing, and in particular to a gradient micro-nano structure Ti- _TiZnX layered composite material and a preparation method thereof.

Background technique

Titanium and titanium alloys are widely used in the aerospace field because of their low density and high specific strength. In addition, due to its light weight, low elastic modulus, excellent comprehensive mechanical properties, non-toxicity, good corrosion resistance and biocompatibility, titanium is widely used in bone transplant materials, dental implants, interventional treatment stents and other scenarios, and is also a good raw material for surgical instruments. However, the titanium material itself still has disadvantages such as a slightly higher elastic modulus than human bones and poor surface activity, which affect the biocompatibility of titanium and cannot meet the various needs of clinical applications. The alloying process is an effective way to reduce the elastic modulus of pure titanium and improve the strength of the material.

Zinc is one of the essential trace elements in the human body. It plays an important role in promoting human growth and development, synthesizing a variety of essential enzymes in the human body, enhancing human immunity, and maintaining normal appetite. It enjoys the reputation of "flower of life" and "source of intelligence". Zinc has good biocompatibility. After implantation into the human body, there is no obvious chronic inflammatory reaction, necrosis or hyperplasia reaction. At the same time, zinc will spontaneously degrade and disappear in the human body environment, and no hydrogen will be produced during degradation. Thanks to its good biological properties and degradable properties, zinc is widely used as a human implant material and plays an important role in human body repair. However, the mechanical properties of zinc are poor and cannot meet the performance requirements of the load-bearing part after implantation; at the same time, the degradation rate of zinc in the human body is difficult to control. When the content of Zn ⁺ in the human body exceeds the threshold, it will cause neurotoxicity; these have limited the free medical use of zinc.

The organic combination of the mechanical and corrosion resistance of titanium or titanium alloys and the biological properties of degradable metallic zinc is the current research focus and hotspot in the field of biomedical metals, and is also an urgent need for high strength, low elasticity, and effective cell growth and fusion in medical metal applications at home and abroad. Studies have shown that when titanium and zinc are implanted into an organism together in a carrier, zinc ions have the effects of "promoting bone formation" and "improving the stability of titanium implants." However, the true composite of titanium and zinc is still a research blind spot in the field of medical materials. Therefore, it is an urgent problem to develop a composite structure between titanium and zinc that is "uniform in phase, can not only play the good mechanical role of titanium, but also can controllably play the biological role of zinc as an essential trace element for the human body, and make the two promote each other's functions", and to form a clear method for preparing the composite structure.

Summary of the invention

One of the purposes of the present invention is to provide a method for preparing a gradient micro-nano structured Ti- _TiZnX layered composite material, so as to solve the problem that it is difficult to prepare titanium-zinc compounds by the existing liquid molding method, so that it is difficult to realize composite medical use of titanium-zinc materials, and to provide a composite structure in which different metal compound layers between titanium and zinc are gradiently distributed and the grain size is at the micro-nano level and a preparation method thereof.

The second object of the present invention is to provide a gradient micro-nanostructured Ti- _TiZnX layered composite material, in which a nanoscale gradient layered structure of titanium-zinc compounds with different atomic ratios such as TiZn ₃ and _TiZnX is formed in the zinc layer region of adjacent pure titanium sheets.

The solution adopted by the present invention to achieve one of the purposes is: a method for preparing a gradient micro-nanostructured Ti- _TiZnX layered composite material, comprising the following steps:

(1) cutting pure titanium sheets and pure zinc sheets into the same size and cleaning the surfaces, stacking and fixing them in sequence to obtain a laminated sheet;

(2) subjecting the laminated sheet obtained in step (1) to a composite rolling process: first hot rolling at a certain temperature, and then cold rolling, to achieve a preliminary combination of the pure titanium and pure zinc sheets, and obtain a pure titanium-pure zinc combination sample;

(3) The rolled pure titanium-pure zinc combined sample is subjected to diffusion heat treatment at a certain temperature to form a gradient micro-nano structure of _TiZn3 and _TiZnX compounds in the zinc layer region between adjacent pure titanium sheets, thereby obtaining the gradient micro-nano structure Ti- _TiZnX layered composite material.

Preferably, in step (1), the thickness of the pure titanium sheet and the pure zinc sheet are both 0.3-0.5 mm.

Preferably, in step (1), the outermost sheet in the laminated sheet is a pure titanium sheet.

Preferably, in step (2), the hot rolling temperature is 350-3400°C.

Hot rolling is selected when the surface flatness of the laminated sheet is poor or the edges are cracked.

Preferably, in step (2), the thickness of the obtained pure titanium-pure zinc bonded sample is reduced from the original thickness of the laminated sheet to 1/331/10 of the original thickness.

Preferably, in the step (2), the specific operation of composite rolling is: placing the fixed laminated sheet in a thin steel plate folded into two pages, using a double-roll mill to first perform hot rolling, and then cold rolling, the double roller hardness of the double-roll mill is higher than that of pure titanium sheet and thin steel plate. First, hot rolling is performed. During hot rolling, the fixed laminated sheet is placed in a thin steel plate folded into two pages, preheated at 350-400°C, and immediately passed through the double roller slit of the rolling mill after being clamped and taken out. According to the degree of sheet bonding, hot rolling and cold rolling are selected alternately, and multiple cold rollings are performed after the first hot rolling. When the surface flatness of the laminated sheet is poor or the boundary is cracked, hot rolling is selected, and then cold rolling is performed.

Preferably, during the rolling process, the double rollers rotate at the same speed of 2310 r/min in opposite directions.

Preferably, in step (3), the diffusion heat treatment is heating to 350-3400° C. in an air atmosphere or an inert gas atmosphere and keeping the temperature for 236 hours.

Preferably, in the step (3), the range of X in the _TiZnX compound is 3-7.

The solution adopted by the present invention to achieve the second purpose is: a gradient micro-nano structure Ti- _TiZnX layered composite material is prepared by the preparation method.

The mechanism of the present invention is as follows:

By laminating pure titanium and pure zinc sheets and then composite rolling them, preliminary mechanical and chemical bonding is achieved between the titanium sheets and the zinc sheets. At the same time, the pure titanium and pure zinc grains are refined, and the grain boundary volume fraction is sharply increased.

Subsequently, the pure titanium-pure zinc combined samples after lamination and composite rolling were subjected to diffusion heat treatment. The high volume fraction of grain boundaries provided favorable channels for atomic diffusion, thereby accelerating the diffusion and reaction of titanium and zinc atoms at high temperatures, and finally forming a nanoscale gradient hierarchical structure of titanium-zinc compounds with different atomic ratios of TiZn ₃ and TiZn _X in the zinc layer area of adjacent pure titanium sheets.

The present invention has the following advantages and beneficial effects:

1. The present invention prepares a Ti- _TiZnX composite layer, and the pure titanium matrix and the compound layer have strong bonding strength and are not easy to crack; that is, a composite material with uniform phase and excellent mechanical properties and good biological properties is prepared between titanium and zinc elements.

2. The present invention forms a composite zone of titanium and zinc elements between pure titanium layers. The composition and organization in the composite zone are distributed in a gradient manner, that is, a gradient layered structure of compounds with different atomic ratios such as TiZn ₃ and TiZn _X is formed. The TiZn ₃ layer is organized as equiaxed crystals with a grain size at the nanometer level.

3. The present invention can adjust the structure and thickness of the titanium-zinc compound layer in the composite area by changing the zinc layer thickness, the diffusion heat treatment temperature, and the diffusion heat treatment time; by changing the zinc layer thickness, the zinc content is adjusted to achieve controllable zinc concentration after implantation in a biological body, making the medical use of zinc safer.

4. The present invention is simple and easy to operate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is an EDS spectrum result corresponding to the composition detection of the Ti- _TiZnX composite layer in Example 1;

Figure 2 is a SEM image of the Ti-TiZn _X composite layer in Example 1, (a) is a low-power wide-view SEM image of the gradient micro-nano Ti-TiZn _X composite layer; (b) is a SEM image of the morphology of the interface between pure titanium and TiZn ₃ ; (c) is a SEM image of the morphology of the TiZn ₃ region; (d) is a SEM image of the morphology of the interface between TiZn ₃ and TiZn _X ;

FIG3 is a SEM image of the interface between TiZn ₃ and TiZn _X in Example 2;

FIG. 4 is a SEM image of the interface between TiZn ₃ and TiZn _X in Comparative Example 1.

Detailed ways

For a better understanding of the present invention, the following examples are provided to further illustrate the present invention, but the present invention is not limited to the following examples.

Embodiment 1:

Four 0.5 mm thick annealed pure titanium sheets and three 0.3 mm thick rolled pure zinc sheets are selected (in other embodiments, pure titanium sheets and pure zinc sheets of appropriate thickness and type can also be selected as needed, without affecting the effect of the prepared composite material), cut into the same size, and arranged in layers with intervals, with the titanium sheet on the outermost side. Holes are drilled at the four corners of the sheet using a mechanical drill, and riveted with aluminum strips to achieve mechanical fixation between the sheet layers.

First, hot rolling is performed. During hot rolling, the fixed laminated sheets are placed in a thin steel plate folded into two pages, heated at 400°C (generally the hot rolling temperature is 350-400°C, 400°C is preferred in this embodiment) for 1h (5min-2h, selected according to demand), and immediately passed through the double roller slit of the rolling mill after being clamped and taken out. According to the degree of sheet bonding, hot rolling and cold rolling are selected alternately, and hot rolling is performed 3 times and cold rolling is performed dozens of times. The initial thickness of the sample is about 3mm, and the final average thickness is 1mm.

The part with better macroscopic bonding of the sample was cut off, cleaned, placed in the furnace cavity of a box furnace, heated to 350°C and kept warm for 2 hours.

After composite rolling and diffusion heat treatment, the EDS spectrum results corresponding to the sample composition detection in Example 1 are shown in Figure 1. In the composite area of titanium and zinc elements, a gradient layered structure of different intermetallic compounds of TiZn ₃ and TiZn _X is formed. In this embodiment, the average value of X in the TiZn _X layer is about 5.7.

After composite rolling and diffusion heat treatment, the structure of the sample in Example 1 is shown in Figure 2. (a) is a low-power wide-view SEM image of the gradient micro-nano Ti/TiZn _X composite layer. It can be seen from the figure that a TiZn ₃ region is formed between the two layers of pure titanium near the pure titanium, and then transitions to the TiZn _X region; (b) is a SEM image of the morphology of the junction between pure titanium and TiZn ₃ ; (c) is a SEM image of the morphology of the TiZn ₃ region, and it can be seen that the structure is a nanoscale equiaxed crystal with twin distribution; (d) is a SEM image of the morphology of the junction between TiZn ₃ and TiZn _X.

Embodiment 2:

Except that the heating and holding temperature in the box furnace is 400° C., the process flow and other process parameters of this embodiment are the same as those of Embodiment 1.

FIG3 is a SEM image of the interface between TiZn ₃ and TiZn _X in Example 2. It can be seen that the structure of the TiZn ₃ region is nanoscale equiaxed crystals. In this embodiment, the value of X in the TiZn _X layer is about 7.

Comparative Example 1:

Except that the heating and holding temperature in the box furnace is 450° C., the process flow and other process parameters of this embodiment are the same as those of Embodiment 1.

Figure 4 is a SEM image of the interface between TiZn ₃ and TiZn _X in Comparative Example 1. It can be seen that the structure of the TiZn ₃ region is nanoscale equiaxed crystals. The value of X in the TiZn _X layer in this embodiment is about 7, but obvious holes are observed in the TiZn ₇ layer, which will reduce the mechanical properties of the material.

The above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principle of the present invention, and these improvements and changes are also regarded as the protection scope of the present invention.

Claims (7)

1. The preparation method of the gradient micro-nano structure Ti-TiZn _X layered composite material is characterized by comprising the following steps of:

(1) Cutting pure titanium sheets and pure zinc sheets into the same size, cleaning the surfaces, sequentially stacking at intervals, and fixing to obtain laminated sheets;

(2) Subjecting the laminated sheet obtained in the step (1) to a clad-rolling treatment: firstly, hot rolling is carried out at 350-400 ℃, and then cold rolling is carried out, so that the primary combination of pure titanium and pure zinc sheets is realized, and a pure titanium-pure zinc combined sample is obtained;

(3) Performing diffusion heat treatment on the rolled pure titanium-pure zinc combined sample at a certain temperature, and forming gradient micro-nano structures of TiZn ₃ and TiZn _X compounds in a zinc layer area in the middle of adjacent pure titanium sheets to obtain the Ti-TiZn _X layered composite material with the gradient micro-nano structure;

In the step (3), the diffusion heat treatment is to heat to 350-400 ℃ in an air atmosphere or an inert gas atmosphere, and keep the temperature for 2-6 hours; the range of X in TiZn _X compounds is 3-7.

2. The method for preparing the gradient micro-nano structure Ti-TiZn _X layered composite material according to claim 1, wherein in the step (1), the thickness of the pure titanium sheet and the pure zinc sheet are both 0.3-0.5mm.

3. The method for preparing a Ti-TiZn _X layered composite material with a gradient micro-nano structure according to claim 1, wherein in the step (1), the outermost side of the laminated sheet is a pure titanium sheet.

4. The method for preparing a Ti-TiZn _X layered composite material with a gradient micro-nano structure according to claim 1, wherein in the step (2), the obtained pure titanium-pure zinc combined sample is reduced from the original thickness of the laminated sheet to 1/3-1/10 of the original thickness.

5. The method for preparing the Ti-TiZn _X layered composite material with the gradient micro-nano structure according to claim 1, wherein in the step (2), the specific operation of the clad-rolling is as follows: the fixed laminated sheet is placed in a thin steel plate folded into two pages, and hot rolling is carried out firstly by adopting a double rolling mill, and then cold rolling is carried out, wherein the hardness of double rollers of the double rolling mill is higher than that of the pure titanium sheet and the thin steel plate.

6. The method for preparing the gradient micro-nano structure Ti-TiZn _X layered composite material according to claim 5, wherein the rotation speed of the double rollers is consistent in the rolling process and is 2-10 r/min, and the directions are opposite.

7. A gradient micro-nano structure Ti-TiZn _X layered composite material is characterized in that: prepared by the preparation method of any one of claims 1-6.