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

Abstract

The invention discloses a Mg-Ba series magnesium alloy and a preparation method and application thereof. The alloy components include Mg and Ba; in terms of mass percentage, the content of Ba in the alloy is 0-10.0 wt. The amount of Mg is Mg; it is prepared by a combination of simultaneous casting and rolling pre-deformation technology and deep plastic processing, and can be used to prepare orthopedic medical implants. The Mg-Ba series alloy of the present invention can be uniformly corroded, has no second phase residue, no release of toxic and harmful elements, and controllable degradation, which ensures that the Mg-Ba series alloy of the present invention has good cell and tissue reaction, and is in the body and bone. Well integrated.

Description

A kind of Mg-Ba series magnesium alloy and its preparation method and application

technical field

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

Background technique

Traditional medical metal materials such as stainless steel and titanium alloy have good mechanical properties and corrosion resistance, and are widely used in clinical practice. However, the long-term retention of such materials as foreign bodies in the body may cause varying degrees of irritation to surrounding tissues, which may result in a series of serious consequences. For example, the elastic modulus of traditional metal internal fixation materials is much higher than that of human bone, and there is a "stress shielding" effect, which easily leads to the lack of sufficient stress stimulation in the bone, resulting in delayed fracture healing and even secondary fractures. For another example, due to the wear of implant materials and the dissolution of harmful ions, it may cause allergic and inflammatory reactions in the human body, and even lead to major diseases such as distortion and inducing cancer in severe cases. In addition, after patients recover from fractures and internal fixation, they often need to undergo a second operation to remove the metal implant, which will bring new and additional clinical pain, infection risk, and economic burden to the patient.

In recent years, the emergence of degradable magnesium alloys provides a new solution to the above problems, so it is called "revolutionary medical metal materials". Degradable magnesium alloys can be gradually corroded and degraded in the body, and the released degradation products can be utilized by the body or excreted from the body, and no implants remain after assisting the tissue to complete repair. Magnesium is an essential macroelement for the human body. It is closely related to the maintenance of life and physical health. It is highly biocompatible, and excess magnesium can be efficiently excreted by the kidneys. The elastic modulus and density of degradable magnesium alloys are similar to those of bone tissue. As orthopaedic implant materials, magnesium alloys can effectively avoid the "stress shielding" effect. In addition, the magnesium ions released from the corrosion degradation of magnesium alloys can effectively induce new bone formation and promote osseointegration. In summary, magnesium alloys have the characteristics of ideal orthopaedic implant materials, and are expected to improve the treatment effect of bone-related diseases such as fractures and bone defects.

However, most of the existing degradable magnesium alloys have problems of rapid degradation, severe local corrosion, poor tissue compatibility, and poor material and osseointegration, which limit their application in orthopaedics to a certain extent. and promotion. To investigate the reason, the electrode potential of most alloying elements in the existing medical magnesium alloys is higher than that of Mg. According to the mixed potential theory, the potential of the second phase formed by these alloying elements and Mg is correspondingly higher than that of the Mg matrix. When a galvanic pair is formed in the environment, the Mg matrix will preferentially corrode, which often leads to excessive corrosion, severe local corrosion and premature failure of the device. In addition, the question of whether these relatively stable second phases can be degraded and eventually metabolized/excreted is still unclear, posing potential medical applications. Therefore, the newly developed degradable magnesium alloy materials should focus on solving the problems of controllable degradation and tissue compatibility. The electrode potential design and regulation of phase composition in magnesium alloys is a potential feasible approach.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings in the prior art, and to provide a Mg-Ba series magnesium with uniform microstructure, suitable mechanical properties, adjustable and controllable degradation, good tissue compatibility, and suitable for orthopedics and other environments. Alloy and its preparation method and application.

The object of the present invention is achieved through the following technical solutions:

An Mg-Ba series magnesium alloy, the alloy components include Mg and Ba; the content of Ba in the alloy is 0-10.0wt. 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 above-mentioned Mg-Ba series magnesium alloy, comprises the following steps:

(1) Weigh high-purity Mg and Ba raw materials, and mix them evenly to obtain a mixture; after vacuuming in an induction furnace (<10 ^{- 2} Pa), fill with argon, or under the protection of a mixed atmosphere of CO ₂ and SF ₆ , to The mixture is smelted to obtain a metal melt;

(2) uniformly feeding the metal melt into two counter-rotating rolls, the metal melt is rapidly cooled, and synchronous casting and rolling are achieved between the rolls to obtain a Mg-Ba series alloy pre-deformed slab;

(3) Deep plastic processing is performed on the Mg-Ba alloy pre-deformed slab, that is, the slab is first homogenized/solution treated at 350-550°C, kept for 5-24h, air-cooled/water-cooled, and then cooled at 150-550°C. Under the condition of 500°C, extrusion, rolling or equal-diameter angular extrusion is carried out to obtain Mg-Ba series magnesium alloy. The Mg-Ba series magnesium alloys can be rods, plates, pipes and wires.

In step (1), the temperature of the smelting is 750-900° C., electromagnetic stirring or mechanical stirring is applied during the smelting process, and the completely melted melt is stirred for 10-30 minutes under heat preservation to ensure that the melt is uniform and no unmelted particles remain.

In step (2), the distance between the roll and the melt outflow outlet, the melt outflow speed, the rotational speed of the roll (preferably 5 to 15 rpm), and the distance between the rolls (preferably 1 to 10 mm) can be regulated to obtain a pre-deformed slab of uniform quality.

In step (3), the process conditions of the extrusion are as follows: the extrusion temperature is 200-500°C, the extrusion ratio is 10-100, the extrusion speed is 0.5-100 mm/s, the extrusion is forward, and the extrusion is performed one at a time. pressure.

In step (3), the process conditions of the rolling are as follows: the rolling temperature is 150-500° C., the reduction in a single pass is 10-40%, and annealing at 100-300° C. can be selected between passes, and the control is different. The rolling direction is the same between passes.

In step (3), the process conditions of the equal-diameter angular extrusion are: adopt the Bc path, the extrusion speed is 0.5-5 mm/s, the extrusion pass is 1-16 times, and the extrusion temperature is 200-500°C.

If conventional smelting and casting methods are used, the eutectic phase of Mg-Ba and other eutectic systems is coarse, and it is difficult to completely break the eutectic phase in subsequent plastic processing, and the microstructure may be uneven, which may lead to local corrosion. In the present invention, pouring and rolling are performed simultaneously in step (2), the pre-deformation process effectively breaks the eutectic structure in the Mg-Ba alloy, improves the deformability of the alloy, and then undergoes subsequent deep plastic processing to ensure the final The obtained Mg-Ba alloy has a uniform structure, uniform and stable properties.

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

The orthopaedic medical implant includes at least one of a bone plate, a bone nail, a bone tissue repair bracket, an intramedullary needle, a bone sleeve, an inducing tissue regeneration membrane, a bone defect patch and a spinal internal fixation device.

In addition, the Mg-Ba series magnesium alloy in the present invention can also be used as a developing marking component on medical implants, and the medical implants include cavities such as blood vessel stents, airway stents, pancreatobiliary stents, urethral stents, etc. At least one of stents and occluders, valves, and intraluminal filters. For example, the use of Mg-Ba magnesium alloys as the visualization marking components at both ends of the vascular stent can significantly enhance the imaging performance of the implant under X-rays, and facilitate the radio-guided interventional procedures and postoperative follow-up inspections.

The principle of the present invention is:

(1) Barium (Ba) is a trace element that naturally exists in the human body. The total amount of Ba in a healthy adult (70kg) is about 16mg; medical barium sulfate containing Ba is not absorbed in the gastrointestinal tract, and there is no allergic reaction. It is used as a gastrointestinal contrast agent; many studies classify Ba as a "non-toxic trace element", and Ba can be metabolized and excreted by the human body; therefore, strictly controlling the content of Ba in magnesium alloys and its release in the body will theoretically not cause local and systemic toxicity;

(2) The solubility of Ba in magnesium is extremely small, and within the Ba content range required by the present invention, Ba added to the magnesium alloy will be in the form of the second phase (Mg ₁₇ Ba ₂ , Mg ₂₃ B ₆ or Mg ₂ Ba) Form precipitation, which plays the role of second phase strengthening, refines the structure, and improves the mechanical properties of medical magnesium alloys;

(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 the electrode potential of the second phase formed in the Mg-Ba alloy is also slightly lower than that of the matrix Mg. ; In the body fluid environment, the second phase particles are preferentially dissolved as the anode; therefore, it can be ensured that both the second phase and the matrix phase in the Mg-Ba alloy can be completely corroded to achieve 100% degradation of the material; this is similar to many other medical Different from magnesium alloys, it avoids the uncertainty of whether the second phase can be degraded in other alloys and whether the degradation products can be metabolized, and improves the safety of the material;

(4) On the basis that the second phase in the Mg-Ba alloy is preferentially corroded by the Mg matrix, the composition of the Mg-Ba alloy, the casting-rolling integration parameters, the homogenization/solution heat treatment conditions and the deep plastic working process can be adjusted. , realize the regulation of the volume fraction/number, size, shape and distribution of the second phase, optimize the mechanical properties, and realize the precise regulation of the degradation behavior of Mg-Ba alloy;

(5) The relative atomic mass of Ba is 137.3, which is about 5.7 times that of Mg (24.3), and its developability under the rays is better than that of Mg. Adding Ba to magnesium alloys can improve the developability of magnesium alloys under X-rays. The implantation procedure and follow-up of certain implants (eg, vascular stents) are beneficial.

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

(1) The present invention uses Ba as the alloying element in Mg for the first time. The standard electrode potential of the second phase in the Mg-Ba series magnesium alloy is lower than that of the matrix Mg, which is preferentially corroded by the matrix, which can ensure that the alloy is completely degraded without any residue.

(2) By combining the simultaneous casting and rolling pre-deformation technology with the deep plastic working method, the number, size, morphology and distribution of the second phase in the Mg-Ba series alloy can be controlled, and the degradation behavior of the Mg-Ba series alloy can be controlled. control, avoid local corrosion, and make the degradation rate controllable and adjustable.

(3) The Mg-Ba series alloy of the present invention can be uniformly corroded, has no second phase residue, no release of toxic and harmful elements, and controllable degradation, which ensures that the Mg-Ba series alloy of the present invention has good cellular and tissue reactions. The body and bone are well integrated.

(4) Mg-Ba alloys have good development under X-ray, which is beneficial to X-ray-guided surgical operation and postoperative imaging follow-up.

Description of drawings

Figure 1 shows the microstructure of the equidistantly extruded Mg-Ba series magnesium alloy.

FIG. 2 is the XRD pattern of the equidistant angularly extruded Mg-Ba series magnesium alloy.

Figure 3 shows the mechanical properties of the as-extruded Mg-Ba series magnesium alloy.

Figure 4 shows the in vitro degradation properties of as-rolled Mg-Ba series magnesium alloys.

Figure 5 shows the in vitro biological properties of extruded Mg-Ba series magnesium alloys.

Figure 6 shows the Micro-CT results of extruded Mg-2Ba alloy implanted in rat femur.

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

Detailed ways

In order to facilitate understanding of the present invention, the present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be pointed out that for those skilled in the art, without departing from the concept of the present invention, the present invention can also make several modifications and improvements, which all belong to the protection scope of the present invention.

Unless otherwise defined, all technical and scientific terms used herein belong to the technical terms commonly used in the technical field of the present invention and have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terms used in the specification herein are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

The following detection methods are adopted to evaluate the materials in the examples and comparative examples, and the corresponding specific detection methods are as follows:

(1) Microstructure

The surface of the sample was mechanically ground with 400-2000# water sandpaper in turn, and finally ground to a smooth and bright surface. The phase identification of the alloy was carried out by X-ray diffractometer (Rugaku Ultima IV). The test parameters are Cu Kα radiation, the tube voltage is 40kV, the scanning range is 10-90°, and the scanning speed is 2°/min. After the sample was etched with 4% nitric acid alcohol, the microstructure was observed using a metallographic microscope (BX51, Olympus).

(2) Mechanical properties

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

(3) Corrosion behavior

According to the ASTM-F746 standard, the electrochemical corrosion behavior of the material was tested by an electrochemical workstation (PGSTAT 302N, MetrohmAutolab). i _corr , and calculate the corrosion rate v _corr . The immersion experiment was carried out with reference to the ASTM F3268-18a standard, the immersion ratio was 20 mL/cm ² , the volume of hydrogen evolution and the reaction corrosion rate were recorded.

(4) Osteogenic properties

After sterilization, the samples were added to DMEM medium (containing 10% fetal bovine serum) according to the material surface area/cell culture medium volume ratio of 1.25 cm ² /mL, and placed in a 37°C, 5% CO ₂ incubator for 24 hours, and the material soaked was obtained. Extraction. Human bone marrow mesenchymal stem cells (hBMMSCs) cells were cultured with the extract, the cell viability was tested by cck-8 method, and the expression of osteogenic differentiation-related genes Runx2, ALP, OCN and OSX was detected by real-time fluorescence quantitative PCR.

(5) Histological response in vivo

The Mg-Ba alloy implants were sterilized by Co60 radiation and implanted into the femurs of female SD rats. 12 weeks after the operation, the femurs of the rats were recovered for subsequent Micro-CT and histological analysis. Micro-CT scanning parameters are set as: voltage 60kV, current 220μA, exposure time 1500ms, effective pixel size 8.82μm. Three-dimensional reconstruction of the implanted bone segment and residual material. The bone segment at the implant site was taken, decalcified, embedded and sliced, and then stained with methylene blue acid fuchsin to observe the formation of new bone, materials and osseointegration.

Example 1

Pure Mg (99.98 wt. %) and pure Ba (99.9 wt. %) raw materials (pure metal/master alloy) were weighed in proportion, and smelted in an induction furnace after mixing sufficiently. After vacuuming (<10 ^-2 Pa), fill with high-purity argon gas as a protective atmosphere, smelt at 800 ° C, apply electromagnetic stirring or mechanical stirring to the melt, and keep the melt for 30 minutes. To the rotating roll, during the cooling process, synchronous casting and rolling are achieved to obtain pre-deformed Mg-Ba alloys with different alloy compositions, including: Mg-0.2Ba, Mg-0.5Ba, Mg-1.0Ba, Mg-2.0 Ba, Mg-10Ba.

Example 2

Referring to the method described in Example 1, smelting at 750-900°C, synchronous casting and rolling, Mg-0.2Ba, Mg-0.5Ba, Mg-1.0Ba and Mg-2.0Ba pre-deformed alloys were obtained. The pre-deformed alloy was homogenized at 400°C for 10 hours, then air-cooled and extruded at equal diameter angles. The Bc path was adopted, the extrusion speed was controlled at 2 mm/s, the extrusion passes were 4 times, and the extrusion temperature was 300°C. After the equal diameter angular extrusion treatment, the grains of the Mg-Ba alloy were further refined and the second phase particles were effectively broken (Fig. 1). X-ray diffraction (XRD) results show that the second phase in the above Mg-Ba alloy is Mg ₁₇ Ba ₂ ( FIG. 2 ).

Example 3

Referring to the method described in Example 1, a Mg-Ba series alloy was prepared. After the pre-deformed alloy was homogenized at 400°C for 10 hours, it was extruded at 300-400°C. The extrusion ratio was controlled to be 25, and the extrusion speed was 4 mm/s. It is extruded to a diameter of 10 mm one at a time to obtain a Mg-Ba binary alloy extruded rod. Room temperature tensile experiments were performed on the obtained Mg-Ba based alloys. It can be found that the addition of Ba significantly improves the tensile properties of magnesium alloys (Fig. 3). When the Ba content is 0.2wt.%, the yield strength (96±6MPa) of the corresponding alloy is still low. When the Ba content increases to 0.5wt.%, the yield strength (121±9MPa) increases by 26% compared with Mg-0.2Ba %. When the Ba content was further increased to 2.0 wt.%, the yield strength was further increased (134±9MPa). The change of tensile strength of as-extruded Mg-Ba alloy with Ba content is consistent with the change of yield strength, that is, it increases with the increase of Ba content. When the Ba content is 2.0wt.%, it has the highest tensile strength (246±3MPa).

Example 4

Referring to the method described in Example 1, a Mg-Ba series alloy was prepared. After the pre-deformed alloy was homogenized at 400 °C for 10 hours, multi-pass rolling was performed. The rolling temperature was 300 °C, and the reduction in each pass was controlled as 20%, and annealing at 250° C. between passes to obtain a rolled sheet with a thickness of 2 mm. The corrosion electrochemical test of the obtained Mg-Ba alloys was carried out. From the potentiodynamic polarization curve, it can be seen that the addition of Ba shifted the overall cathode curve to the lower left, and the corrosion potential of the alloy was lower (Fig. 4(a). In the design of Mg-Ba alloys, the electrode potential of Ba is lower than that of Mg, and the addition of Mg to Mg causes the potential of the alloy to decrease. At the same time, Ba and Mg form the second phase Mg ₁₇ Ba ₂ , which is lower than Mg from the mixed potential theory. The matrix, Mg ₁₇ Ba ₂ will corrode preferentially to the matrix. The measured electrochemical corrosion parameters are listed in Table 1. It can be seen that after adding Ba alloying, the open circuit potential and corrosion potential of the alloy are lower, and the corrosion current density and corrosion current density in the short term are lower. The corrosion rate is comparable to that of pure magnesium. The volume of hydrogen evolution in the immersion experiment intuitively reflects the corrosion behavior of the material in a longer period of time (Fig. 4(b)). It can be seen that when the Ba content is 0.2wt.% and 0.5wt% .%, the hydrogen evolution amount is equivalent; when the Ba content is increased to 1.0wt.%, the hydrogen evolution amount after soaking for 10d is 5.9mL/cm ² , which is only about 1/3 of the strong two. Further increase the Ba content to 2wt.%. %, the amount of hydrogen evolution after 10d is only 0.8mL/cm ² , which is even lower than that of pure Mg group. No uncorroded Mg ₁₇ Ba ₂ phase was found in the corrosion product layer, indicating that the material can be completely degraded. The results of immersion experiments confirmed that , because the electrode potential of Mg ₁₇ Ba ₂ is lower than that of the Mg matrix, but only slightly lower than that of the Mg matrix, it will not significantly accelerate the corrosion of magnesium alloys, or make the corrosion uncontrollable and unpredictable. On the contrary, by adjusting the alloy composition, through the casting and The control of the alloy microstructure (grain size, number, size, shape and distribution of the second phase, etc.) by rolling integrated pre-deformation treatment, heat treatment and deep plastic working can realize the regulation of the corrosion behavior and corrosion rate of Mg-Ba series alloys. The corrosion rate of Mg-Ba alloys can be adjusted according to the requirements of the use site.

Table 1 Electrochemical corrosion parameters of as-rolled Mg-Ba series alloys

Test Example 1

The osteogenic properties of the as-extruded Mg-Ba alloy obtained in Example 3 were evaluated. Because Mg-1Ba corrodes faster in DMEM medium and releases too many metal ions, it can inhibit the activity of hBMMSCs to a certain extent (Fig. 5(a)). The cell compatibility can be improved by adjusting the corrosion rate. The in vivo environment itself has a strong buffering capacity, and it is generally believed that the local ion concentration is much lower than the in vitro test environment. The rest of the Mg-Ba alloys were not toxic to hBMMSCs cells, and the cytocompatibility of the materials was good. Furthermore, the effects of typical Mg-2Ba alloys on the expression of osteogenic genes were investigated. It can be seen that the addition of Ba in Mg can significantly increase the expression levels of osteogenesis-related genes (Runx2, ALP, OCN and OSX) (Fig. 5(b)). In vitro cell experiments confirmed that Mg-Ba alloys have good cell compatibility and are beneficial to osteogenic differentiation.

Test case 2

The Mg-2Ba alloy prepared in Example 3 was implanted into the rat femur for 12 w (with pure Mg and Mg-1Ca as the control), Micro-CT results showed that the edge of the Mg-2Ba alloy was clear and flat, and the corrosion was uniform, showing Significantly better corrosion resistance, while pure Mg has jagged edges, indicating faster corrosion and severe localized corrosion (Fig. 6). Mg-1.0Ca alloys also show a certain degree of localized corrosion. There is no obvious hydrogen cavity around the Mg-2Ba implant, and the material is closely connected with the bone cortex. However, obvious gas cavities were seen around the Mg implants, and the material was poorly integrated with the osseointegration. The Micro-CT results also showed that the contrast of the Mg-2Ba implant was significantly higher than that of the Mg and Mg-1Ca implants, proving its better visualization under X-ray. The results of methylene blue acid fuchsin staining of Mg-2Ba alloy hard tissue sections (Fig. 7) showed that the surrounding tissue of Mg-2Ba implants grew well, no obvious inflammatory reaction was observed, and the material was closely combined with bone tissue, indicating that Mg-2Ba alloy is closely related to bone tissue. Compatible with bone tissue, good osseointegration. However, obvious air cavities were seen in the tissue section of the Mg implant, and the material and osseointegration were not well integrated, which was consistent with the results of Micro-CT (Fig. 6).

Comparative Example 1

Referring to the methods described in Example 1 and Example 3, extruded pure Mg was prepared. Upon testing, pure Mg consists of a single α-Mg phase with no secondary phase. The yield strength and tensile strength of pure Mg are 66 ± 6 MPa and 170 ± 2 MPa, respectively, which are significantly lower than the Mg-Ba alloys of the examples of the present invention ( FIG. 3 ). The electrochemical corrosion rate of pure Mg falls within the corrosion rate range of Mg-Ba series alloys (Table 1). Pure Mg was not toxic to hBMMSCs, but the expression level of osteogenic genes was significantly lower than that of Mg-Ba alloy (Fig. 5). The pure Mg implanted in the rat femur showed obvious local corrosion at 12w after operation. The corrosion was too fast and the hydrogen was released too much, resulting in the existence of air cavity around the Mg implant, resulting in poor osteogenesis and osseointegration (Figure 6, Figure 6). 7).

Comparative Example 2

Referring to the methods described in Examples 1 and 3, extruded Mg-1Ca alloys were prepared. It should be noted that Ca and Ba are elements of the same family, 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 the Mg ₂ Ca second phase corrodes preferentially over the Mg matrix. After testing, the comprehensive mechanical properties of Mg-1Ca are comparable to those of the Mg-Ba alloys in Examples 2-6. Mg-1Ca was not toxic to hBMMSCs cells, and the osteogenic gene expression level was slightly higher than that of pure Mg, but still significantly lower than that of Mg-Ba alloy (Fig. 5). The Mg-1Ca implanted in the rat femur still showed a certain degree of local corrosion at 12w after operation, and there was less new bone formation at the local corrosion site (Fig. 7), and the overall performance in vivo was not as good as that of the Mg-1Ba alloy.

Comparative Example 3

The Mg-2Ba as-cast alloy was obtained by conventional smelting (800 ℃) and casting method. After the as-cast alloy was homogenized at 400 ℃ for 10 hours, it was rolled in multiple passes at a rolling temperature of 300 ℃. Controlled to 20%, annealing treatment at 250° C. was performed between passes to obtain a rolled sheet with a thickness of 2 mm. Through microstructure observation, it is found that there is a coarse Mg ₁₇ Ba _second phase in the Mg-2Ba alloy that has been conventionally cast and rolled, and the distribution of the second phase is uneven, and the microstructure is not as good as the embodiment of the present invention (fine, uniform). ). The immersion corrosion test found that the conventionally cast and rolled Mg-2Ba alloy had obvious local corrosion, and the hydrogen evolution amount after 10 days was 3.2 mL/cm ² , which was much higher than that of the Mg-2Ba alloy of the same composition in Example 4 (0.8 mL/cm ² ).

The above are only examples of the present invention, but the embodiments of the present invention are not limited by the above examples, and any other changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principle of the present invention , are all equivalent replacement modes, and are all included in the protection scope of the present invention.

Claims (8)

1. A Mg-Ba series magnesium alloy, characterized in that: the alloy components include Mg and Ba; in terms of mass percentage, the content of Ba in the alloy is 0 to 10.0 wt.%, but 0 is not included, and the remainder is Mg. 2 . The Mg-Ba based magnesium alloy according to claim 1 , wherein the content of the Ba is 0.2-7.0 wt. %. 3 . 3. a preparation method of the Mg-Ba system magnesium alloy described in claim 1 or 2, is characterized in that comprising the following steps: (1) Weigh high-purity Mg and Ba raw materials, mix them evenly, and obtain a mixture; after vacuuming in an induction furnace, fill with argon gas or under the protection of a mixed atmosphere of CO ₂ and SF ₆ , and smelt the mixture to obtain metal melt; (2) uniformly feeding the metal melt into two counter-rotating rolls, the metal melt is rapidly cooled, and synchronous casting and rolling are achieved between the rolls to obtain a Mg-Ba series alloy pre-deformed slab; (3) Deep plastic processing is performed on the Mg-Ba alloy pre-deformed slab, that is, the slab is first homogenized/solution treated at 350-550°C, kept for 5-24h, air-cooled/water-cooled, and then cooled at 150-550°C. Under the condition of 500°C, extrusion, rolling or equal-diameter angular extrusion is carried out to obtain Mg-Ba series magnesium alloy. 4. The preparation method of Mg-Ba system magnesium alloy according to claim 3, characterized in that: in step (1), the temperature of the smelting is 750～900 ℃, and electromagnetic stirring or mechanical stirring is applied in the smelting process, The completely molten melt is kept stirring for 10-30 minutes. 5. the preparation method of Mg-Ba system magnesium alloy according to claim 3, is characterized in that: in step (2), can regulate and control the distance between the roller and the melt outflow outlet, the melt outflow speed, the rotational speed of the roller, the inter-roller distance to obtain pre-deformed slabs with uniform quality. 6. The preparation method of Mg-Ba series magnesium alloy according to claim 3, characterized in that: in step (3), the extrusion process conditions are: extrusion temperature is 200-500 DEG C, extrusion ratio is 10 to 100, the extrusion speed is 0.5 to 100 mm/s, and the forward extrusion is performed one time at a time; the technological conditions of the rolling are: the rolling temperature is 150 to 500 ° C, and the single pass reduction is 10～40%, annealing at 100～300℃ can be selected between passes, and the rolling direction between different passes is controlled to be consistent; the process conditions of the equal-diameter angular extrusion are: adopt the Bc path, and the extrusion speed is 0.5～5mm /s, the extrusion passes are 1 to 16 times, and the extrusion temperature is 200 to 500°C. 7. An application of the Mg-Ba system magnesium alloy according to claim 1 or 2, characterized in that: the application in the preparation of an orthopedic medical implant; the orthopedic medical implant comprises a bone plate, a bone nail, At least one of a bone tissue repair scaffold, an intramedullary needle, a bone sleeve, an inducing tissue regeneration membrane, a bone defect patch and a spinal internal fixation device. 8. An application of the Mg-Ba system magnesium alloy according to claim 1 or 2, characterized in that: it is used as a developing marking component on a medical implant, and the medical implant comprises a cavity support, a seal At least one of occluder, valve and intraluminal filter.

Images