阅读说明：本技术 一种超高压力作用下的Mg-Sc-X合金及其制备方法 (Mg-Sc-X alloy under ultrahigh pressure and preparation method thereof ) 是由 林继兴 徐临超 童先 陈健军 张德闯 蔡文昊 高尧 王坤 于 2019-12-11 设计创作，主要内容包括：本发明涉及一种超高压力作用下的Mg-Sc-X合金及其制备方法,按质量百分比计包括如下成份：Sc18～22wt.％,X0.05～0.5wt.％,所述X选自Zn、Cu、Zr中的至少一种,余量为Mg,所述Mg-Sc-X合金的压力值为1GPa～6GPa级,所述Mg-Sc-X合金的压缩屈服强度为160～185MPa、压缩极限强度为325～380MPa,以提供一种压缩力学性能高、耐腐蚀和血液相容性优异的超高压力作用下的Mg-Sc-X(X＝Zn、Cu、Zr)合金及其制备方法。(The invention relates to a Mg-Sc-X alloy under the action of ultrahigh pressure and a preparation method thereof, wherein the Mg-Sc-X alloy comprises the following components in percentage by mass: the alloy comprises, by weight, 18-22% of Sc and 0.05-0.5% of X, wherein the X is selected from at least one of Zn, Cu and Zr, and the balance is Mg, the pressure value of the Mg-Sc-X alloy is in the level of 1-6 GPa, the compressive yield strength of the Mg-Sc-X alloy is 160-185 MPa, and the compressive ultimate strength of the Mg-Sc-X alloy is 325-380 MPa, so that the Mg-Sc-X (X ═ Zn, Cu and Zr) alloy under the action of ultrahigh pressure with high compressive mechanical property, corrosion resistance and excellent blood compatibility and the preparation method thereof are provided.)

1. An Mg-Sc-X alloy under the action of ultrahigh pressure, which is characterized in that: comprises the following components by mass percent: the alloy material comprises, by weight, Sc 18-22%, and X0.05-0.5%, wherein X is selected from at least one of Zn, Cu and Zr, and the balance is Mg, the pressure value of the Mg-Sc-X alloy is in the range of 1 GPa-6 GPa, the yield strength of the Mg-Sc-X alloy is 160-185 MPa, and the compressive strength is 325-380 MPa.

2. An ultra-high pressure Mg-Sc-X alloy according to claim 1, wherein: the Mg-Sc-X alloy has an elongation of 21-53% and a hardness value of 97-120 HV.

3. A method for producing an alloy of Mg-Sc-X under ultra high pressure according to any of claims 1 to 2, comprising the steps of:

a. with SF having a gas percentage concentration of 1 vol%₆And the balance of CO₂Under the protection of mixed atmosphere, smelting in a vacuum resistance furnace, and covering with a magnesium alloy second flux;

b. pouring the alloy melt into a cast steel mold preheated to 250 ℃ to obtain an alloy cast ingot;

c. carrying out heat preservation on the cast ingot at 300-350 ℃ for 5-10 h, carrying out homogenization annealing, and preparing a cylindrical sample with the diameter of 9-11mm and the length of 14-16mm by wire cutting;

d. performing a high-pressure experiment by using a high-pressure cubic press, setting the pressure to be 1 GPa-6 GPa, and setting the heating temperature to be 700-1300 ℃ according to a Clausius-Clapeyren equation and by combining the melting point of each alloy;

e. sequentially loading a cylindrical sample into boron nitride, a graphite sleeve and pyrophyllite to form an assembly sleeve, then placing the assembly sleeve into a cavity position of a high-pressure cubic press, and starting a high-pressure solidification and heat treatment experiment after aligning a hammer head;

f. and (4) conducting heat by virtue of equipment, quickly cooling to room temperature, finally releasing pressure and taking out a sample to obtain a finished product.

4. A method for preparing Mg-Sc-X alloy under ultra-high pressure according to claim 3, wherein: the main raw materials of the Mg-Sc-X alloy used for smelting are as follows: mg ingot with the purity of 99.9 percent, Mg-30 percent Sc intermediate alloy, pure Zn ingot with the purity of 99.99 percent, pure Cu wire with the purity of 99.9 percent, pure Sr grain with the purity of 99.5 percent and Mg-30 percent Zr intermediate alloy are weighed according to the mass ratio of three simple substances in the components of the Mg-Sc-X alloy.

5. A method for preparing Mg-Sc-X alloy under ultra-high pressure according to claim 3, wherein: in the step a, the melting temperature of the smelting is 750-900 ℃, and the smelting is kept for 30 minutes at the temperature so as to fully melt the raw materials.

6. A method for preparing Mg-Sc-X alloy under ultra-high pressure according to claim 3, wherein: and in the step b, pouring after the pouring temperature is reduced to 700-750 ℃.

7. A method for preparing Mg-Sc-X alloy under ultra-high pressure according to claim 3, wherein: and step e, increasing the pressure to a preset pressure, starting a water cooling device in the temperature measuring device and opening the high-pressure cubic press equipment, quickly increasing the temperature to the preset temperature at a heating speed of 300 ℃/min, preserving heat and pressure at the temperature for 10-60 min, and then stopping heating.

Technical Field

The invention relates to the technical field of biodegradable medical magnesium alloy, in particular to Mg-Sc-X alloy under the action of ultrahigh pressure and a preparation method thereof.

Background

Magnesium alloys are promising and widely accepted as candidates for degradable bone implants due to their satisfactory mechanical properties, acceptable biodegradation rate, good biocompatibility and superior bone-forcing ability, furthermore, the young's modulus (41-45 GPa) of magnesium alloys is close to that of human bone (around 30 GPa), thus avoiding the "stress shielding" effect, so far, magnesium alloys containing Rare Earth Elements (REE) have been widely studied as orthopedic implants, WE43 alloys (Y: 4 wt.%, Nd and Gd mixed metal: 3 wt.%) show excellent mechanical properties and good corrosion resistance, MAGNEZIX MgYREZr compressed bone nails and gmaris coronary stents, with compositions similar to WE43 alloys, european safety eligibility (CE) was obtained in 2013 and 2016, respectively, and the current clinical follow-up results are relatively satisfactory for further improvement of the in vivo corrosion resistance of magnesium alloys as well as the strengthening of magnesium alloy by the mechanical corrosion of Mg-X (Mg-X, Dy) alloys, Mg-Dy alloy, Mg-Sc alloys, Sc-Sc, Sc.

According to the Mg-Sc phase diagram, under the appropriate scandium content range, a β -phase Mg-Sc alloy can be obtained at room temperature by adopting appropriate heat treatment and a rapid solidification process.

Until now, no research on the reported Mg-Sc-X (X ═ Zn, Cu and Zr) alloy under the action of ultrahigh pressure (GPa grade) and a preparation method thereof is found, so that the application of the Mg-Sc-X (X ═ Zn, Cu and Zr) alloy under the action of high pressure as a degradable biomedical material at the next stage is proposed.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the Mg-Sc-X alloy with high compression mechanical property, corrosion resistance and excellent blood compatibility under the action of ultrahigh pressure and the preparation method thereof.

The technical scheme of the invention is realized as follows: the Mg-Sc-X alloy under the action of ultrahigh pressure and the preparation method thereof comprise the following components by mass percent: the alloy material comprises, by weight, Sc 18-22%, and X0.05-0.5%, wherein X is selected from at least one of Zn, Cu and Zr, and the balance is Mg, the pressure value of the Mg-Sc-X alloy is in the range of 1 GPa-6 GPa, the compressive yield strength of the Mg-Sc-X alloy is 160-185 MPa, and the compressive ultimate strength is 325-380 MPa.

By adopting the technical scheme, the compression mechanical property and the hardness value of the high-pressure Mg-Sc-X alloy are obviously improved, the alloy shows a more corrected corrosion potential and lower corrosion current density and corrosion rate after high-pressure treatment, has more excellent corrosion resistance, and the alloy leaching liquor shows lower hemolysis rate and has more excellent blood compatibility after high-pressure treatment.

The invention is further configured to: the Mg-Sc-X alloy has an elongation of 21-53% and a hardness value of 97-120 HV

By adopting the technical scheme, the mechanical property of the Mg-Sc-X alloy is further improved.

The invention is further configured to: the method comprises the following steps:

a. with SF having a gas percentage concentration of 1 vol%₆And the balance of CO₂Under the protection of mixed atmosphere, smelting in a vacuum resistance furnace, and covering with a magnesium alloy second flux;

b. pouring the alloy melt into a cast steel mold preheated to 250 ℃ to obtain an alloy cast ingot;

c. carrying out heat preservation on the cast ingot at 300-350 ℃ for 5-10 h, carrying out homogenization annealing, and preparing a cylindrical sample with the diameter of 9-11mm and the length of 14-16mm by wire cutting;

d. performing a high-pressure experiment by using a high-pressure cubic press, setting the pressure to be 1 GPa-6 GPa, and setting the heating temperature to be 700-1300 ℃ according to a Clausius-Clapeyren equation and by combining the melting point of each alloy;

e. sequentially loading a cylindrical sample into boron nitride, a graphite sleeve and pyrophyllite to form an assembly sleeve, then placing the assembly sleeve into a cavity position of a high-pressure cubic press, and starting a high-pressure solidification and heat treatment experiment after aligning a hammer head;

f. and (4) conducting heat by virtue of equipment, quickly cooling to room temperature, finally releasing pressure and taking out a sample to obtain a finished product.

By adopting the technical scheme, the Mg-Sc-X alloy containing different elements can be prepared by the steps, the preparation efficiency is greatly improved, the precision is higher, and the use in medical clinic is easier to meet.

The invention is further configured to: the main raw materials of the Mg-Sc-X alloy used for smelting are as follows: mg ingot with the purity of 99.9 percent, Mg-30 percent Sc intermediate alloy, pure Zn ingot with the purity of 99.99 percent, pure Cu wire with the purity of 99.9 percent, pure Sr grain with the purity of 99.5 percent and Mg-30 percent Zr intermediate alloy are weighed according to the mass ratio of three simple substances in the components of the Mg-Sc-X alloy.

By adopting the technical scheme, the material with more accurate data is obtained by adopting the high-purity material, so that the use is facilitated.

The invention is further configured to: in the step a, the melting temperature of the smelting is 750-900 ℃, and the smelting is kept for 30 minutes at the temperature so as to fully melt the raw materials.

By adopting the technical scheme, the accuracy of experimental data is greatly improved, and the preparation efficiency is greatly improved.

The invention is further configured to: and in the step b, pouring after the pouring temperature is reduced to 700-750 ℃.

By adopting the technical scheme, the difference of experimental data obtained by different temperatures can be conveniently compared, so that the working efficiency is improved.

The invention is further configured to: and step e, increasing the pressure to a preset pressure, starting a water cooling device in the temperature measuring device and opening the high-pressure cubic press equipment, quickly increasing the temperature to the preset temperature at a heating speed of 300 ℃/min, preserving heat and pressure at the temperature for 10-60 min, and then stopping heating.

By adopting the technical scheme, the performance of the prepared material is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a metallographic microstructure of an Mg-20Sc-0.2Zn alloy before and after autoclaving in accordance with an embodiment of the present invention;

FIG. 2 is an XRD pattern of an Mg-20Sc-0.2Zn alloy before and after autoclaving in accordance with an embodiment of the present invention;

FIG. 3 is a graph of the compressive deformation curve and corresponding compressive property data and hardness values of Mg-20Sc-0.2Zn alloy before and after high pressure treatment in accordance with an embodiment of the present invention;

FIG. 4 is a table comparing high pressure alloys with as-cast data according to embodiments of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 to 4, in example 1, the invention discloses a Mg-Sc-X (X ═ Zn, Cu, Zr) alloy under ultrahigh pressure and a preparation method thereof, and Mg ingots with purity of 99.9%, Mg-30% Sc master alloy, and pure Zn ingots with purity of 99.99% are firstly adopted and weighed according to the mass ratio of three ingots in Mg-20Sc-0.2Zn alloy components. By using SF₆(1 vol.%) and the balance CO₂Under the protection of the mixed atmosphere, smelting in a vacuum resistance furnace, and covering with a magnesium alloy second flux, wherein the components of the magnesium alloy second flux are MgCl 2-46%, KCl 32-40%, CaF2 3-5%, BaCl2 5.5-8.5%, NaCl + CaCl2 not more than 8%, insoluble substances not more than 1.5%, MgO not more than 1.5%, water content not more than 3%, and the melting temperature is 750 ℃, and keeping for 30 minutes at the temperature so as to fully melt the raw materials. When the casting temperature is reduced to 720 ℃, the alloy melt is cast into a steel casting mold preheated to 250 DEG CTo obtain the alloy ingot. Carrying out heat preservation on the cast ingot at 300 ℃ for 8h for carrying out homogenization annealing, preparing a cylindrical sample with the diameter of 10mm and the length of 15mm by wire cutting, carrying out a high-pressure experiment by using a high-pressure cubic press, setting the pressure to be 5GPa, combining the melting point of each alloy according to a Clausius-Clapeyren equation which is a first latent heat release equation, and calculating according to the formula to obtain the heating temperature of 1165 ℃ when the melting point of the magnesium alloy is increased by 1GPa and the melting point is increased by 75 ℃. And sequentially filling the cylindrical sample into boron nitride, a graphite sleeve and pyrophyllite to form an assembly sleeve, then putting the assembly sleeve into a cavity position of a high-pressure six-side top, and starting a high-pressure solidification and heat treatment experiment after aligning the hammer. Firstly, the pressure is increased to a preset pressure, and simultaneously, a water cooling device in the temperature measuring device is started and a cubic press device is opened. Rapidly heating to a preset temperature at a heating speed of 300 ℃/min. And (3) keeping the temperature and the pressure for 25min at the temperature, stopping heating, quickly cooling to room temperature by means of heat conduction of equipment, finally relieving the pressure and taking out a sample to obtain a finished product.

In summary, the following experimental data were obtained:

1. the Mg-20Sc-0.2Zn alloy prepared in this example had a Sc element content of 19.92% by relative mass, a Zn element content of 0.23% by relative mass and the balance Mg as measured by X-ray fluorescence spectroscopy (XRF). The melting point of the Mg-20Sc-0.2Zn alloy was 781.6 ℃ as measured by Differential Scanning Calorimetry (DSC).

2. In the as-cast Mg-20Sc-0.2Zn alloy, which is composed mainly of a white α -Mg matrix and a black color, the high-pressure treatment resulted in the presence of a black β -Sc phase in addition to a white α -Mg phase, and white grain boundaries were present in the high-pressure sample, with a grain size of 415.2. + -. 23.4. mu.m.

3. The cast Mg-20Sc-0.2Zn alloy mainly consists of α -Mg phase which is solid solution with a close-packed hexagonal structure, and after high-pressure treatment, besides α -Mg phase, β -Sc phase with higher content exists, which shows that the Mg-20Sc-0.2Zn alloy after high-pressure treatment has phase change, and a part of α -Mg phase is converted into β -Sc phase, which is consistent with the change trend of the metallographic structure in figure 1.

4. The Compressive Yield Strength (CYS), compressive ultimate strength (UCS), elongation, and hardness values of the as-cast Mg-20Sc-0.2Zn alloy were 122.2MPa, 287.0MPa, 17.9%, and 82.4HV, respectively. After high-pressure treatment, the compressive mechanical property and the hardness value of the high-pressure Mg-20Sc-0.2Zn alloy are obviously improved, and the Compressive Yield Strength (CYS), the compressive ultimate strength (UCS), the elongation and the hardness value are respectively 162.1MPa, 329.8MPa, 22.6 percent and 98.7 HV.

5. Electrochemical tests in Hank's solution show that the corrosion potential, the corrosion current density and the corrosion rate of the as-cast Mg-20Sc-0.2Zn alloy are-1.214V and 186.1 muA/cm²And 4.2 mm/y. After high-pressure treatment, the corrosion potential, the corrosion current density and the corrosion rate of the high-pressure Mg-20Sc-0.2Zn alloy are-1.137V and 153.2 mu A/cm²And 3.4 mm/y. After high-pressure treatment, the corrosion-resistant alloy shows more positive corrosion potential and lower corrosion current density and corrosion rate, and has more excellent corrosion resistance. Immersion experiments in Hank's solution gave as-cast Mg-20Sc-0.2Zn alloys with a corrosion rate of 0.43 mm/y. After high-pressure treatment, the corrosion rate of the high-pressure Mg-20Sc-0.2Zn alloy is 0.32mm/y, which is consistent with the change rule of data measured by an electrochemical experiment.

6. In mouse ischemia platelet plasma (PPP), the hemolysis rate of the cast Mg-20Sc-0.2Zn alloy leaching solution is 4.83%. After high-pressure treatment, the hemolysis rate of the high-pressure Mg-20Sc-0.2Zn alloy leaching liquor is reduced to 3.21 percent due to the improvement of the corrosion resistance of the alloy. The hemolysis rate of the Mg-20Sc-0.2Zn alloy leaching liquor in the two states is lower than 5 percent, and the requirement of clinical medical biological materials on the hemolysis rate is met. The alloy leaching liquor after high-pressure treatment has lower hemolysis rate and more excellent blood compatibility.