CN114855040A

CN114855040A - Mg-Ba series magnesium alloy and preparation method and application thereof

Info

Publication number: CN114855040A
Application number: CN202210462940.7A
Authority: CN
Inventors: 郑玉峰; 刘洋; 夏丹丹; 边东; 成艳
Original assignee: Peking University
Current assignee: Peking University
Priority date: 2022-04-28
Filing date: 2022-04-28
Publication date: 2022-08-05
Anticipated expiration: 2042-04-28
Also published as: CN114855040B

Abstract

The invention discloses a Mg-Ba series magnesium alloy and a preparation method and application thereof, wherein the alloy comprises Mg and Ba; the content of Ba in the alloy is 0-10.0 wt.%, but not 0, and the balance is Mg; the preparation method combines the synchronous pouring and rolling pre-deformation technology with the deep plastic processing means, and can be used for preparing the orthopedic medical implant. The Mg-Ba series alloy of the invention can be corroded uniformly, has no second phase residue, has no release of toxic and harmful elements and can be degraded controllably, thereby ensuring that the Mg-Ba series alloy of the invention has good cell and tissue reaction and good integration with bones in vivo.

Description

Mg-Ba series magnesium alloy and preparation method and application thereof

Technical Field

The invention belongs to the field of medical degradable metal materials, and particularly relates to Mg-Ba series magnesium alloy and a preparation method and application thereof.

Background

Traditional medical metal materials such as stainless steel, titanium alloy and the like have good mechanical properties and corrosion resistance, and are widely applied clinically. However, the long-term persistence of such materials in the body as foreign bodies can cause varying degrees of irritation to surrounding tissues and can thus have a range of serious consequences. For example, the elastic modulus of the traditional metal internal fixation material is far higher than that of human bone, and the traditional metal internal fixation material has a stress shielding effect, which easily causes the lack of sufficient stress stimulation in the bone, so that the healing of the fracture is slow, and even secondary fracture is induced. In another example, the implant material may be abraded and the harmful ions may be dissolved out, which may cause allergic and inflammatory reactions in the human body, and in severe cases, may even cause serious diseases such as distortion and induction of canceration. In addition, after the patients with internal fracture fixation and the like are cured, the metal implants are usually taken out through a secondary operation, which brings new and additional clinical operation pain, infection risk and economic burden to the patients.

In recent years, the appearance of degradable magnesium alloys has provided a new solution to the above problems, and thus they are called "revolutionary medical metal materials". The degradable magnesium alloy can be gradually corroded and degraded in vivo, the released degradation product can be utilized by the organism or be discharged out of the body, and no implant is remained after the tissue is assisted to be repaired. Magnesium is a necessary macro element for human bodies, has close relation with life maintenance and body health, is highly biocompatible, and can efficiently discharge excess magnesium through kidneys. The elasticity modulus and density of the degradable magnesium alloy are similar to those of bone tissues, and the degradable magnesium alloy can effectively avoid the stress shielding effect when being used as an orthopedic implant material. In addition, magnesium ions released by corrosion degradation of the magnesium alloy can effectively induce new osteogenesis and promote osseointegration. In summary, the magnesium alloy has the characteristics of an ideal orthopedic implant material, and is expected to improve the treatment effect of bone-related diseases such as fracture, bone defect and the like.

However, most of the existing degradable magnesium alloys have the problems of over-rapid degradation, severe local corrosion, poor tissue compatibility and poor integration of materials and bones, which limits the application and popularization of the degradable magnesium alloys in orthopedics to a certain extent. The reason is deeply studied, the electrode potential of most alloying elements in the existing medical magnesium alloy is higher than that of Mg, according to the mixed potential theory, the potential of a second phase formed by the alloying elements and Mg is correspondingly higher than that of a Mg matrix, the alloying elements and the Mg matrix form galvanic couples in a liquid environment, the Mg matrix is corroded preferentially, and the corrosion is over fast, the local corrosion is serious and the appliance fails prematurely. Furthermore, the problem of whether these relatively stable second phases can degrade and eventually be metabolized/excreted remains unclear, with medical application concerns. Therefore, the newly developed degradable magnesium alloy material should mainly solve the problems of controllable degradation and tissue compatibility, and the design and regulation of the electrode potential of the phase composition in the magnesium alloy are potential feasible ways.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide the Mg-Ba series magnesium alloy which has uniform microstructure, proper mechanical property, adjustable and controllable degradation and good tissue compatibility and is suitable for being used in environments such as orthopedics and the like, and the preparation method and the application thereof.

The purpose of the invention is realized by the following technical scheme:

an Mg-Ba series magnesium alloy comprises Mg and Ba; the content of Ba in the alloy is 0-10.0 wt.%, but not 0, and the balance is Mg. Preferably, the content of Ba is 0.2-7.0 wt.%. Further preferably, the content of Ba is 0.2-2.0 wt.%.

The preparation method of the Mg-Ba series magnesium alloy comprises the following steps:

(1) weighing high-purity Mg and Ba raw materialsUniformly mixing to obtain a mixture; after evacuation in an induction furnace (< 10) ^- ² Pa), argon or CO is filled ₂ And SF ₆ Under the protection of mixed atmosphere, smelting the mixture to obtain metal melt;

(2) uniformly feeding the metal melt into two rollers rotating in opposite directions, rapidly cooling the metal melt, and synchronously pouring and rolling between the rollers to obtain a Mg-Ba alloy pre-deformed slab;

(3) and carrying out deep plastic processing on the Mg-Ba alloy pre-deformed plate blank, namely homogenizing/solution-treating the plate blank at 350-550 ℃, preserving heat for 5-24 h, carrying out air cooling/water cooling, and then carrying out extrusion, rolling or equal channel angular extrusion treatment at 150-500 ℃ to obtain the Mg-Ba alloy. The Mg-Ba series magnesium alloy can be bars, plates, pipes and wires.

In the step (1), the smelting temperature is 750-900 ℃, electromagnetic stirring or mechanical stirring is applied in the smelting process, and the completely molten melt is stirred for 10-30 min under heat preservation, so that the melt is uniform and has no residual unmelted particles.

In the step (2), the distance between the roller and the melt outflow port, the melt outflow speed, the roller rotation speed (preferably 5-15 rpm) and the distance between the rollers (preferably 1-10 mm) can be regulated and controlled, so that the pre-deformed plate blank with uniform quality is obtained.

In the step (3), the extrusion process conditions are as follows: the extrusion temperature is 200-500 ℃, the extrusion ratio is 10-100, the extrusion speed is 0.5-100 mm/s, and the forward extrusion and the one-step extrusion are carried out.

In the step (3), the rolling process conditions are as follows: the rolling temperature is 150-500 ℃, the single-pass rolling reduction is 10-40%, annealing at 100-300 ℃ can be selected between passes, and the rolling directions of different passes are controlled to be consistent.

In the step (3), the process conditions of the equal channel angular extrusion are as follows: adopting a Bc path, wherein the extrusion speed is 0.5-5 mm/s, the extrusion pass is 1-16 times, and the extrusion temperature is 200-500 ℃.

If a conventional smelting and pouring method is adopted, eutectic phases in eutectic systems such as Mg-Ba and the like are large, the eutectic phases are difficult to completely break through subsequent plastic processing, and the microstructure of a micro-area is possibly inhomogeneous, so that local corrosion is possibly caused. In the invention, the casting and rolling are synchronously carried out in the step (2), the eutectic structure in the Mg-Ba alloy is effectively crushed in the pre-deformation process, the alloy deformation capability is improved, and the finally obtained Mg-Ba alloy can be ensured to have uniform structure, uniform and stable performance through subsequent deep plastic processing.

The invention also provides application of the Mg-Ba series magnesium alloy in preparation of orthopedic medical implants.

The orthopedic medical implant comprises at least one of a bone plate, a bone nail, a bone tissue repair bracket, an intramedullary needle, a bone sleeve, an induced tissue regeneration membrane, a bone defect patch and a spine internal fixation material.

In addition, the Mg-Ba series magnesium alloy can also be used as a developing marking component on a medical implant, and the medical implant comprises at least one of a lumen stent such as a vascular stent, an airway stent, a pancreatic biliary stent, a urethral stent and the like, and a stopper, a valve and a lumen filter. For example, Mg-Ba magnesium alloy is used as developing and marking components at two ends of the vascular stent, so that the developing performance of the implant under X rays can be obviously enhanced, and the interventional operation process and the postoperative follow-up examination under the guidance of the rays are convenient.

The principle of the invention is as follows:

(1) barium (Ba) is a trace element naturally present in the human body, and the total amount of Ba in healthy adults (70kg) is about 16 mg; medical barium sulfate containing Ba is not absorbed in gastrointestinal tract and has no anaphylactic reaction, and is used as gastrointestinal tract contrast agent; many studies have classified Ba as a "non-toxic trace element" that can be metabolized by the body; therefore, the Ba content and the in-vivo release amount thereof in the magnesium alloy are strictly controlled, and the local and system toxicity is not caused theoretically;

(2) the solubility of Ba in magnesium is extremely small and Ba added to the magnesium alloy will be in the second phase (Mg) within the range of Ba content required in the present invention ₁₇ Ba ₂ 、Mg ₂₃ B ₆ Or Mg ₂ Ba) is precipitated, so that a second phase strengthening effect is achieved, the structure is refined, and the mechanical property of the medical magnesium alloy is improved;

(3) the standard electrode potentials of Mg and Ba are-2.37V and-2.91V respectively, the standard electrode potential of Ba is slightly lower than that of Mg, so that the electrode potential of a second phase formed in the Mg-Ba alloy is also slightly lower than that of matrix Mg; in a body fluid environment, the second phase particles preferentially dissolve as anodes; therefore, it can be ensured that both the second phase and the matrix phase in the Mg-Ba alloy can be completely corroded, achieving 100% degradation of the material; different from other medical magnesium alloys, the uncertainty of whether the second phase can be degraded or not and whether the degradation product can be metabolized in other alloys is avoided, and the safety of the material is improved;

(4) based on the fact that a second phase in the Mg-Ba alloy is corroded in preference to a Mg matrix, the volume fraction/quantity, the size, the shape and the distribution of the second phase can be regulated and controlled by adjusting the components of the Mg-Ba alloy, casting-rolling integrated parameters, homogenization/solution heat treatment conditions and a deep plastic processing technology, the mechanical property is optimized, and the degradation behavior of the Mg-Ba alloy is accurately regulated and controlled;

(5) the relative atomic mass of Ba is 137.3 which is about 5.7 times of Mg (24.3), the developing performance under the radiation is better than that of Mg, and the adding of Ba in the magnesium alloy can improve the developing performance of the magnesium alloy under the X-ray, which is beneficial to the implantation operation and the subsequent follow-up of some implants (such as vascular stents).

Compared with the prior art, the invention has the following advantages and effects:

(1) the invention takes Ba as an alloy element in Mg for the first time, and the standard electrode potential of a second phase in the Mg-Ba series magnesium alloy is lower than that of matrix Mg and is corroded in preference to the matrix, so that the alloy can be completely degraded without any residue.

(2) The quantity, size, form and distribution of second phases in the Mg-Ba alloy are regulated and controlled by combining a synchronous pouring and rolling pre-deformation technology with a deep plastic processing means, so that the degradation behavior of the Mg-Ba alloy can be regulated and controlled, the occurrence of local corrosion is avoided, and the degradation speed is controllable and adjustable.

(3) The Mg-Ba series alloy of the invention can be corroded uniformly, has no second phase residue, has no release of toxic and harmful elements and can be degraded controllably, thereby ensuring that the Mg-Ba series alloy of the invention has good cell and tissue reaction and good integration with bones in vivo.

(4) The Mg-Ba alloy has good developing property under X-ray, and is beneficial to the operation under the guidance of X-ray and the imaging follow-up after operation.

Drawings

FIG. 1 shows a microstructure of an equi-diametric angle-extruded Mg-Ba series magnesium alloy.

FIG. 2 is an XRD pattern of an isometric angle extruded Mg-Ba series magnesium alloy.

FIG. 3 shows the mechanical properties of an extruded Mg-Ba series magnesium alloy.

FIG. 4 shows the in vitro degradation performance of rolled Mg-Ba series magnesium alloy.

FIG. 5 shows the in vitro biological properties of the Mg-Ba series magnesium alloy in an extruded state.

FIG. 6 shows the results of Micro-CT of the Mg-2Ba alloy in the extruded state after being implanted into rat femur.

FIG. 7 shows the results of staining methylene blue acid fuchsin after implantation of the extruded Mg-2Ba alloy into rat femur.

Detailed Description

In order that the invention may be readily understood, reference will now be made in detail to the specific embodiments of the invention. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that, for a person skilled in the art, many variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein are to be interpreted as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The materials in the examples and comparative examples were evaluated using the following detection methods, the corresponding specific detection methods were as follows:

(1) microstructure of

The surface of the sample is sequentially mechanically polished by 400-2000# waterproof abrasive paper, and finally polished until the surface is smooth and bright. The alloy phase identification is carried out by an X-ray diffractometer (Rugakuultima IV). The test parameters are Cu Ka radiation, the tube voltage is 40kV, the scanning range is 10-90 degrees, and the scanning speed is 2 degrees/min. After the sample was etched with 4% nital, the microstructure was observed using a metallographic microscope (BX51, Olympus).

(2) Mechanical properties

Standard tensile specimens were cut according to ASTM-E8-04 and tensile tests were carried out on a universal tester (Instron 5969) at room temperature and at a tensile test rate of 1 mm/min. Yield Strength (YS), tensile strength (UTS), and elongation (EL.) values were obtained from the tensile curve.

(3) Corrosion behaviour

According to the ASTM-F746 standard, an electrochemical workstation (PGSTAT 302N, MetrohmAutolab) is utilized to test the electrochemical corrosion behavior of the material, selected simulated body fluid is Hank's solution, and a potentiodynamic polarization test is carried out at the scanning rate of 1mV/s to obtain the corrosion current density i _corr And calculating the corrosion rate v _corr . Soaking test was carried out according to ASTM F3268-18a, at a soaking ratio of 20mL/cm ² The hydrogen evolution volume and the reaction corrosion rate were recorded.

(4) Osteogenic Properties

After sterilization, the sample was 1.25cm in terms of the ratio of the surface area of the material to the volume of the cell culture medium ² Adding DMEM medium (containing 10% fetal calf serum) into the mixture, and placing the mixture at 37 ℃ and 5% CO ₂ And (5) incubating for 24h in the incubator to obtain a material leaching liquor. Culturing human bone marrow mesenchymal stem cells (hBMMSCs) by using the leaching solution, testing the activity of the cells by a cck-8 method, and detecting the expression conditions of genes Runx2, ALP, OCN and OSX related to osteogenic differentiation by a real-time fluorescent quantitative PCR experiment.

(5) In vivo histological response

The Mg-Ba alloy implant is irradiated and sterilized by Co60 rays, implanted into femal SD rat thighbone, 12w after operation, the rat thighbone is recovered for subsequent Micro-CT and histological analysis. The Micro-CT scanning parameters are set as follows: voltage 60kV, current 220 mua, exposure time 1500ms, effective pixel size 8.82 μm. And performing three-dimensional reconstruction on the implanted bone segments and the residual material. And (3) taking a bone section of an implanted part, decalcifying, embedding and slicing, dyeing with methylene blue acid fuchsin, and observing the formation of new bones and the integration of materials and bones.

Example 1

Pure Mg (99.98 wt.%) and pure Ba (99.9 wt.%) are weighed proportionally, mixed thoroughly and smelted in induction furnace. After vacuum pumping (< 10) ^-2 Pa), introducing high-purity argon as a protective atmosphere, smelting at 800 ℃, applying electromagnetic stirring or mechanical stirring to the melt, keeping the temperature for 30min, introducing the uniform melt into two rollers rotating in opposite directions, and realizing synchronous pouring and rolling in the cooling process to obtain the pre-deformed Mg-Ba series alloy with different alloy components, wherein the method comprises the following steps of: mg-0.2Ba, Mg-0.5Ba, Mg-1.0Ba, Mg-2.0Ba and Mg-10 Ba.

Example 2

The pre-deformed alloys Mg-0.2Ba, Mg-0.5Ba, Mg-1.0Ba and Mg-2.0Ba were obtained after melting at 750-900 ℃, simultaneous casting and rolling according to the method described in example 1. Homogenizing at 400 deg.C for 10 hr, air cooling, performing equal channel angular extrusion, adopting Bc path, and controlling extrusion speed at 2mm/s, extrusion pass at 4 times, and extrusion temperature at 300 deg.C. After the equal channel angular extrusion treatment, the Mg-Ba alloy grains are further refined obviously, and the second phase particles are effectively crushed (figure 1). The X-ray diffraction (XRD) result showed that the second phase in the above Mg-Ba alloy was Mg ₁₇ Ba ₂ (FIG. 2).

Example 3

The Mg-Ba system alloy is prepared by the method described in the embodiment 1, the pre-deformed alloy is extruded at 400 ℃ for 10 hours after being homogenized at 400 ℃, the extrusion ratio is controlled to be 25, the extrusion speed is controlled to be 4mm/s, and the diameter is extruded to be 10mm in one time, so that the Mg-Ba binary alloy extruded bar is obtained. The obtained Mg — Ba alloy was subjected to a room temperature tensile test. It was found that the addition of Ba significantly improved the tensile properties of the magnesium alloy (fig. 3). When the Ba content is 0.2 wt.%, the yield strength (96 ± 6MPa) of the corresponding alloy is still low, and when the Ba content is increased to 0.5 wt.%, the yield strength (121 ± 9MPa) is increased by 26% compared to Mg-0.2 Ba. Further increasing the Ba content, up to 2.0 wt.%, further increases the yield strength (134 ± 9 MPa). The tensile strength of the as-extruded Mg-Ba alloy is consistent with the yield strength variation with Ba content, i.e., increases with increasing Ba content, with the highest tensile strength (246 ± 3MPa) at a Ba content of 2.0 wt.%.

Example 4

The Mg-Ba alloy was prepared by the method described in example 1, and the pre-deformed alloy was subjected to homogenization treatment at 400 ℃ for 10 hours, then to multi-pass rolling at 300 ℃ with the rolling reduction per pass controlled to 20%, and to 250 ℃ annealing treatment between passes to obtain a rolled sheet having a thickness of 2 mm. The obtained Mg-Ba alloy was subjected to electrochemical corrosion test, and it was found from the zeta potential curve that the addition of Ba shifted the cathode curve as a whole to the left and lower, and the corrosion potential of the alloy was lower (FIG. 4 (a). in the Mg-Ba alloy design, the electrode potential of Ba was lower than that of Mg, and the addition of Ba to Mg caused a decrease in the alloy potential ₁₇ Ba ₂ The mixed potential theory shows that the potential is lower than that of Mg matrix, Mg ₁₇ Ba ₂ Will corrode preferentially to the substrate. The measured electrochemical corrosion parameters are listed in table 1, and it can be seen that after the alloy is alloyed by adding Ba, the open circuit potential and corrosion potential values of the alloy are lower, and the corrosion current density and corrosion rate in a short period are equivalent to those of pure magnesium. The hydrogen evolution volume in the soaking experiment intuitively reflects the corrosion behavior of the material over a longer period of time (fig. 4(b)), and it can be seen that the amount of hydrogen evolution is comparable when the Ba content is 0.2 wt.% and 0.5 wt.%; when the Ba content increased to 1.0 wt.%, the amount of hydrogen evolution after 10d soaking was 5.9mL/cm ² The strength of both is about 1/3. Further increasing the Ba content to 2 wt.%, and the hydrogen evolution amount after 10 days is only 0.8mL/cm ² Even lower than the hydrogen evolution of the pure Mg group. No unetched Mg was found in the corrosion product layer ₁₇ Ba ₂ Phase, indicating that the material is completely degradable. The soaking experiment result proves that the Mg is caused ₁₇ Ba ₂ The electrode potential is lower than the Mg matrix but only slightly lower than the Mg matrix, so that the corrosion of the magnesium alloy is not accelerated obviously or is uncontrollable and unpredictable. In contrast, the microstructure (grain size, number of second phases, size) of the alloy is regulated and controlled by adjusting the alloy composition, and by integrated pre-deformation treatment, heat treatment and deep plastic working of casting and rollingSize, shape, distribution, etc.) can realize the control of the corrosion behavior and corrosion rate of Mg-Ba alloy. The corrosion speed of the Mg-Ba alloy can be regulated and controlled according to the requirements of the using parts.

TABLE 1 rolled Mg-Ba based alloy electrochemical corrosion parameters

Test example 1

The extruded Mg-Ba-based alloy obtained in example 3 was evaluated for the osteogenesis property. Since Mg-1Ba corrodes faster in DMEM medium, excessive metal ions are released, the activity of hBMMSCs is inhibited to a certain extent (figure 5(a)), and the cell compatibility can be improved by adjusting the corrosion rate. The in vivo environment itself has a very strong buffering capacity, generally considered that the local ion concentration is much lower than the in vitro test environment. The rest Mg-Ba alloy does not generate toxicity to hBMMSCs cells, and the cell compatibility of the material is good. Further, the effect of a typical Mg-2Ba alloy on osteogenic gene expression was examined. It can be seen that the addition of Ba in Mg can significantly increase the expression level of the osteogenesis related genes (Runx2, ALP, OCN and OSX) (fig. 5 (b)). In vitro cell experiments prove that the Mg-Ba alloy has good cell compatibility and is beneficial to osteogenic differentiation.

Test example 2

12w after implantation of the Mg-2Ba alloy prepared in example 3 into rat femur (with pure Mg and Mg-1Ca as controls), Micro-CT results showed that the Mg-2Ba alloy had clear and flat edges, uniform corrosion, and exhibited significantly better corrosion resistance, while the pure Mg edges exhibited jagged shapes, indicating faster corrosion and severe localized corrosion (FIG. 6), and the Mg-1.0Ca alloy also exhibited localized corrosion to some extent. There is no obvious hydrogen cavity around the Mg-2Ba implant, and the material is tightly connected with cortical bone. However, significant gas voids were visible around the Mg implant, and the material was poorly integrated with the bone. The Micro-CT results also show that the Mg-2Ba implants have significantly higher contrast than the Mg and Mg-1Ca implants, demonstrating superior developability under X-rays. The methylene blue acid fuchsin staining result of the Mg-2Ba alloy hard tissue section shows (figure 7), the tissue around the Mg-2Ba implant grows well, no obvious inflammatory reaction is seen, the material is tightly combined with the bone tissue, and the Mg-2Ba alloy is compatible with the bone tissue and has good osseointegration. However, the Mg implant tissue sections showed significant air cavities, poor material and bone integration, consistent with the Micro-CT results (FIG. 6).

Comparative example 1

Pure Mg was prepared in an extruded state by the method described in reference to examples 1 and 3. Pure Mg was tested to consist of a single α -Mg phase, with no second phase. The yield strength and the tensile strength of pure Mg are respectively 66 +/-6 MPa and 170 +/-2 MPa, which are obviously lower than those of the Mg-Ba alloy (shown in figure 3) of the embodiment of the invention. The electrochemical corrosion rate of pure Mg falls within the range of Mg-Ba based alloy corrosion rates (Table 1). Pure Mg is not toxic to hBMMSCs cells, but osteoblast gene expression levels are significantly lower than Mg-Ba series alloys (fig. 5). Pure Mg implanted into rat femurs has obvious local corrosion at 12w after operation, the corrosion is too fast, hydrogen is released too much, air cavities around Mg implants exist, and osteogenesis and osseointegration are poor (fig. 6 and 7).

Comparative example 2

An extruded Mg-1Ca alloy was prepared by the method described in reference to examples 1 and 3. It should be noted that Ca and Ba are elements of the same group, the maximum solid solubility of Ca in Mg is 1.34 wt.%, and the solid solubility at room temperature is also low. The electrode potential of Ca is also slightly lower than that of Mg, so Mg ₂ The Ca second phase corrodes preferentially to the Mg matrix. The comprehensive mechanical properties of Mg-1Ca were found to be equivalent to those of the Mg-Ba alloy of examples 2 to 6. Mg-1Ca has no toxicity to hBMMSCs cells, and can induce osteogenic gene expression level slightly higher than pure Mg, but still significantly lower than Mg-Ba series alloy (figure 5). Mg-1Ca implanted into rat femur still shows a certain degree of local corrosion at 12w after operation, new bone formation at local corrosion sites is less (figure 7), and the surface of the Mg-1Ba alloy is not as good as the whole.

Comparative example 3

Obtaining Mg-2Ba as-cast alloy by adopting a conventional smelting (800 ℃) and pouring method, carrying out multi-pass rolling on the as-cast alloy after homogenizing treatment for 10h at 400 ℃, controlling the rolling temperature to be 300 ℃ and the reduction per pass to be 20%, and carrying out annealing treatment at 250 ℃ between passes to obtain a rolled plate with the thickness of 2mm. The microstructure observation shows that the thick Mg exists in the Mg-2Ba alloy after the conventional casting and rolling ₁₇ Ba ₂ The second phase is unevenly distributed, and the microstructure is not as fine and uniform as in the embodiment of the invention. The immersion corrosion test shows that the Mg-2Ba alloy which is conventionally cast and rolled has obvious local corrosion, and the hydrogen evolution quantity after 10 days is 3.2mL/cm ² Much higher than that of the Mg-2Ba alloy (0.8 mL/cm) of the same composition in example 4 ² )。

The above description is only an example of the present invention, but the present invention is not limited to the above example, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention and are equivalent to each other are included in the protection scope of the present invention.

Claims

1. An Mg-Ba series magnesium alloy is characterized in that: the alloy components comprise Mg and Ba; the content of Ba in the alloy is 0-10.0 wt.%, but not 0, and the balance is Mg.

2. The Mg-Ba magnesium alloy according to claim 1, characterized in that: the content of Ba is 0.2-7.0 wt.%.

3. A method for producing a Mg-Ba series magnesium alloy according to claim 1 or 2, characterized by comprising the steps of:

(1) weighing high-purity Mg and Ba raw materials, and uniformly mixing to obtain a mixture; vacuumizing in an induction furnace, and introducing argon or CO ₂ And SF ₆ Under the protection of mixed atmosphere, smelting the mixture to obtain metal melt;

(3) and carrying out deep plastic processing on the Mg-Ba alloy pre-deformed plate blank, namely homogenizing/solution-treating the plate blank at 350-550 ℃, preserving heat for 5-24 h, carrying out air cooling/water cooling, and then carrying out extrusion, rolling or equal channel angular extrusion treatment at 150-500 ℃ to obtain the Mg-Ba alloy.

4. The method for producing a Mg-Ba magnesium alloy according to claim 3, characterized in that: in the step (1), the smelting temperature is 750-900 ℃, electromagnetic stirring or mechanical stirring is applied in the smelting process, and the completely molten melt is stirred for 10-30 min under heat preservation.

5. The method for producing a Mg-Ba magnesium alloy according to claim 3, characterized in that: in the step (2), the distance between the roller and the melt outflow port, the melt outflow speed, the roller rotation speed and the distance between the rollers can be regulated and controlled, and the pre-deformed plate blank with uniform quality is obtained.

6. The method for producing a Mg-Ba magnesium alloy according to claim 3, characterized in that: in the step (3), the extrusion process conditions are as follows: extruding at 200-500 ℃ at an extrusion ratio of 10-100 at an extrusion speed of 0.5-100 mm/s, forward extruding, and extruding for one time; the rolling process conditions are as follows: the rolling temperature is 150-500 ℃, the single-pass rolling reduction is 10-40%, annealing at 100-300 ℃ can be selected between passes, and the rolling directions of different passes are controlled to be consistent; the process conditions of the equal channel angular extrusion are as follows: adopting a Bc path, wherein the extrusion speed is 0.5-5 mm/s, the extrusion pass is 1-16 times, and the extrusion temperature is 200-500 ℃.

7. An application of the Mg-Ba series magnesium alloy of claim 1 or 2, which is characterized in that: the application in preparing orthopedic medical implant; the orthopedic medical implant comprises at least one of a bone plate, a bone nail, a bone tissue repair bracket, an intramedullary needle, a bone sleeve, an induced tissue regeneration membrane, a bone defect patch and a spine internal fixation material.

8. Use of the Mg-Ba magnesium alloy according to claim 1 or 2, characterized in that: the developing mark component is used on a medical implant, and the medical implant comprises at least one of a cavity channel bracket, an occluder, a valve and an intra-cavity filter.