CN107541632A - A kind of bio-medical Mg Zn Zr magnesium alloys and preparation method thereof - Google Patents

Abstract

The invention provides a biomedical Mg-Zn-Zr magnesium alloy and a preparation method thereof. The alloy components and the mass percentages of each component are: Zn: 0.8-3.0%, Zr: 0.4-0.8%, and the rest are Mg and unavoidable impurities. The invention adds alloy elements Zn and Zr to the magnesium alloy to improve the mechanical properties and corrosion resistance of the magnesium alloy; at the same time, the Zn and Zr are harmless elements to ensure that the alloy does not endanger human health after degradation by the human body. The preparation method of the biomedical Mg-Zn-Zr magnesium alloy of the present invention obtains the biomedical magnesium alloy through raw material smelting, casting and solution treatment, and the preparation method is simple to implement and has low production cost. The invention has the advantages that the precipitated phase of the Mg-Zn-Zr magnesium alloy is less, which is beneficial to reduce galvanic corrosion; the uniformity of the structure after solid solution is improved, and the mechanical properties of the alloy are effectively improved. The invention can be applied in the field of biomaterials such as degradable bone plates, bone nails and blood vessel brackets.

Description

A kind of biomedical Mg-Zn-Zr magnesium alloy and preparation method thereof

technical field

The invention relates to the technical field of alloys, in particular to a biomedical Mg-Zn-Zr magnesium alloy and a preparation method thereof.

Background technique

Since the 1990s, biomaterials science has entered a stage of rapid development, and the technological development is changing with each passing day, showing an extremely broad prospect. Implant materials such as traditional stainless steel, titanium alloy, and cobalt-chromium alloy cannot degrade by themselves in the human body, and a second operation is required to remove the implant, which not only increases medical costs, but also brings more pain to patients and causes complications during the operation. complications. In addition, the elastic modulus of commonly used metal hard tissue repair materials is quite different from that of human bone, which will cause a serious stress shielding effect, resulting in reduced bone strength, inhibiting the growth of new bone, and slowing tissue healing.

The elastic modulus of magnesium is far lower than that of stainless steel and titanium alloys, and is closer to that of human bone, which can largely alleviate the stress shielding effect after being implanted in the human body. At the same time, the standard potential of magnesium is very low, and it is easily corroded and degraded in a solution containing chloride ions. If it is used as an implant material, secondary operations can be avoided. And considering that magnesium is a basic element in human metabolism and bone tissue, most of the implanted magnesium material can be excreted from the human body after degradation, and a small amount of it will not cause adverse effects in the human body.

However, magnesium has poor corrosion resistance due to its low standard potential and loose and porous corrosion products. After being implanted in the human body, the degradation rate is too fast, and it will fail before the tissue is healed, affecting the growth and healing of the injured tissue. Therefore, the rapid degradation of magnesium alloys in the human body has become the biggest problem limiting its application in the biomedical field. Alloying is a commonly used method to improve the corrosion resistance of magnesium. Zn is an essential element that exists in large amounts in the human body, and its strengthening effect is second only to Al. Zr is the most effective grain refiner among magnesium alloy elements, which can significantly reduce the grain size to improve the mechanical properties and corrosion resistance of the alloy, and Zr also has the effect of purifying the alloy structure.

In addition, the mechanical properties of magnesium are also low, so it is necessary to take corresponding measures to improve its mechanical properties and meet the performance requirements required as an implant material. Alloying, fine grain strengthening, and heat treatment are often used to improve the mechanical properties of magnesium alloys, and have good results. A reasonable solution treatment process helps to improve the mechanical properties of magnesium alloys. At the same time, the number of second phases in magnesium alloys after solution treatment is reduced and the structure is more uniform, which is conducive to reducing corrosion and improving the corrosion resistance of magnesium alloys. .

Contents of the invention

Aiming at the shortcomings of existing biomedical materials, the invention provides a biomedical material Mg-Zn-Zr magnesium alloy and a preparation method thereof. The alloy also has good biocompatibility, mechanical properties and corrosion resistance.

The invention provides a biomedical Mg-Zn-Zr magnesium alloy. The components and mass percentages of the alloy are: Zn: 0.8-3.0%, Zr: 0.4-0.8%, and the rest are Mg and unavoidable impurities.

The invention provides a method for preparing a biomedical Mg-Zn-Zr magnesium alloy, which specifically includes the following steps:

A. Using high-purity magnesium ingots, zinc ingots, and Mg-30% Zr master alloys as raw materials, alloy melting is carried out in a vacuum induction melting furnace. After the above-mentioned raw materials are melted, they are stirred and cast into ingots. Except for Mg, Zn, and Zr, all other elements exist in the form of impurities;

B. The as-cast alloy is subjected to solid solution treatment in a box-type electric furnace.

The step A specifically includes: under an argon protective atmosphere, add magnesium ingots, zinc ingots and covering agents to a vacuum induction melting furnace, raise the temperature to 760-780°C, add Mg-Zr master alloy, and continue melting to obtain a melt , cast ingots. The ingot includes 0.8-3.0% Zn and 0.4-0.8% Zr, and the rest is Mg and unavoidable impurities.

The step B is specifically: carrying out solution treatment of the cast alloy in a box-type electric furnace, the solution temperature is 390-410° C., and the solution time is 24 hours. In order to prevent oxidation, a certain amount of pyrite (FeS2 ) as protection.

Among the raw materials, Mg≥99.99% in the high-purity magnesium ingot and the rest are impurities; Zn≥99.99% in the high-purity zinc ingot and the rest are impurities; the Zr content in the Mg-30%Zr master alloy is 28-30%, and the impurity Content ≤ 0.01%, the rest is Mg.

The advantages and positive effects that the present invention has are:

(1) The present invention adds alloy elements Zn and Zr to the magnesium alloy to improve the mechanical properties and corrosion resistance of the magnesium alloy; at the same time, Zn and Zr belong to elements that are harmless to the human body, so as to ensure that the alloy does not harm the human body after being degraded by the human body healthy.

(2) The preparation method of the biomedical Mg-Zn-Zr magnesium alloy of the present invention obtains the biomedical magnesium alloy through raw material smelting, casting and solid solution treatment. The preparation method is simple to implement and low in production cost.

(3) The advantages of the present invention are that the Mg-Zn-Zr magnesium alloy has less precipitated phases, which is conducive to reducing galvanic corrosion; the uniformity of the structure after solid solution is improved, and the mechanical properties of the alloy are effectively improved.

Description of drawings

Fig. 1 is the X-ray diffraction pattern of biomedical Mg-Zn-Zr magnesium alloy in embodiment 2;

Fig. 2 is the metallographic diagram of the solid solution state alloy in the preparation process of biomedical Mg-Zn-Zr magnesium alloy in embodiment 2;

Fig. 3 is the metallographic diagram of the solid solution state alloy in the preparation process of the biomedical Mg-Zn-Zr magnesium alloy in embodiment 3;

Fig. 4 is the average corrosion rate of the solid solution alloy in the immersion process during the preparation process of the biomedical Mg-Zn-Zr magnesium alloy in Examples 1, 2 and 3.

Detailed ways

The following is a detailed description of the embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and provides detailed implementation and specific operation process.

Example 1

Use magnesium ingots with Mg purity ≥ 99.99%, zinc ingots with Zn purity ≥ 99.99%, and Mg-30% Zr master alloy with purity ≥ 99.99% as raw materials, weigh the raw materials according to the proportion, and place the magnesium ingots in an argon protective atmosphere. , zinc ingot and covering agent are added to the vacuum induction melting furnace, the temperature is raised to 760°C, the Mg-Zr master alloy is added, the melt is obtained by continuous melting, and the ingot is obtained by casting. The ingot contains 0.90% Zn and 0.44% Zr, and the balance is Mg and unavoidable impurities. The as-cast alloy is subjected to solution treatment in a box-type electric furnace. The solution temperature is 390°C and the solution time is 24 hours. In order to prevent oxidation, a certain amount of pyrite (FeS2) is added as a protection.

The properties of the alloy obtained in this embodiment are as follows: tensile strength 169MPa, yield strength 97MPa, elongation 18%, hardness 41HV; average corrosion rate after soaking in Hank's solution for 240 hours is 0.87mm/year.

Example 2

Use magnesium ingots with Mg purity ≥ 99.99%, zinc ingots with Zn purity ≥ 99.99%, and Mg-30% Zr master alloy with purity ≥ 99.99% as raw materials, weigh the raw materials according to the proportion, and place the magnesium ingots in an argon protective atmosphere. , zinc ingot and covering agent are added to the vacuum induction melting furnace, the temperature is raised to 780°C, the Mg-Zr master alloy is added, the melt is obtained by continuous melting, and the ingot is obtained by casting. The ingot contains 1.87% Zn and 0.54% Zr, the rest being Mg and unavoidable impurities. The as-cast alloy is subjected to solution treatment in a box-type electric furnace. The solution temperature is 400°C and the solution time is 24 hours. In order to prevent oxidation, a certain amount of pyrite (FeS2) is added as a protection.

The properties of the alloy obtained in this embodiment are as follows: tensile strength 210MPa, yield strength 118MPa, elongation 23%, hardness 49HV; average corrosion rate after soaking in Hank's solution for 240 hours is 0.35mm/year.

Example 3

Use magnesium ingots with Mg purity ≥ 99.99%, zinc ingots with Zn purity ≥ 99.99%, and Mg-30% Zr master alloy with purity ≥ 99.99% as raw materials, weigh the raw materials according to the proportion, and place the magnesium ingots in an argon protective atmosphere. , zinc ingot and covering agent are added to the vacuum induction melting furnace, the temperature is raised to 770°C, the Mg-Zr master alloy is added, the melt is obtained by continuous melting, and the ingot is obtained by casting. The ingot contains 2.75% Zn and 0.56% Zr, and the rest is Mg and unavoidable impurities. The as-cast alloy is subjected to solution treatment in a box-type electric furnace. The solution temperature is 410°C and the solution time is 24 hours. In order to prevent oxidation, a certain amount of pyrite (FeS2) is added as a protection.

The properties of the alloy obtained in this embodiment are as follows: tensile strength 224MPa, yield strength 112MPa, elongation 24%, hardness 47HV; average corrosion rate after soaking in Hank's solution for 240 hours is 0.63mm/year.

Claims (5)

1. A biomedical Mg-Zn-Zr magnesium alloy, characterized in that the components contain Zn, Zr and Mg; the mass percentages of each component are: Zn: 0.8-3.0%, Zr: 0.4-0.8 %, the rest is Mg and unavoidable impurities. 2. a preparation method of biomedical Mg-Zn-Zr magnesium alloy as claimed in claim 1, is characterized in that comprising the following steps: A. Using high-purity magnesium ingots, zinc ingots, and Mg-30% Zr intermediate alloys as raw materials, alloy melting is carried out in a vacuum induction melting furnace; after the above-mentioned raw materials are all melted, they are stirred and cast into ingots, except for Mg, Except for Zn and Zr, other elements exist in the form of impurities; B. The as-cast alloy is subjected to solid solution treatment in a box-type electric furnace. 3. the preparation method of biomedical Mg-Zn-Zr magnesium alloy according to claim 2 is characterized in that, described step A is specifically: under argon protective atmosphere, add magnesium ingot, zinc ingot and covering agent Put it into a vacuum induction melting furnace, raise the temperature to 760-780°C, add Mg-Zr master alloy, continue melting to obtain a melt, and cast to obtain an ingot; the ingot includes 0.8-3.0% Zn and 0.4-0.8% Zr , and the rest are Mg and unavoidable impurities. 4. the preparation method of biomedical Mg-Zn-Zr magnesium alloy according to claim 2 is characterized in that, described step B is specially: carry out solid solution treatment with as-cast alloy in box-type electric furnace, solid solution temperature The temperature is 390-410℃, and the solid solution time is 24 hours. In order to prevent oxidation, a certain amount of pyrite FeS ₂ is added as a protection. 5. The preparation method of biomedical Mg-Zn-Zr magnesium alloy according to claim 2 is characterized in that: Mg≥99.99% in the high-purity magnesium ingot, and the rest are impurities; Zn≥99.99% in the high-purity zinc ingot, The rest are impurities; the Zr content in the Mg-30%Zr master alloy is 28-30%, the impurity content is ≤0.01%, and the rest is Mg.