CN103074511B - Medical multi-hole implanted alloy material and preparation method thereof - Google Patents

Abstract

The invention discloses a medical porous implant alloy material, which is composed of an alloy containing Ti, Ta, Nb and Zr four elements, and contains a plurality of macropores with a diameter of 200-500 μm. There are several small pores with a diameter of 5-30 μm; the porosity of the porous body is ≥30%. The medical porous implant material of the invention does not contain any toxic elements, has lower modulus and better biocompatibility. The invention provides a method for preparing the medical porous implant alloy material, which has the following advantages: 1) Personalized design can be carried out for different patients; 2) It has the characteristics of rapidity, accuracy and good at making entities with complex shapes; 3) No need for molds, reducing manufacturing costs; 4) The porosity of macropores and the connectivity between macropores can be freely adjusted to promote the ingrowth of bone tissue and adjust the mechanical properties of the implant such as strength and modulus; 5) Forming Carrying out in a vacuum environment is conducive to the utilization of active metals.

Description

A kind of medical porous implant alloy material and preparation method thereof

technical field

The invention relates to the field of biomedical materials, in particular to a medical porous implant alloy material and a preparation method thereof.

Background technique

Titanium alloy has good corrosion resistance and mechanical properties, and is an ideal biomedical metal material. At present, titanium alloys widely used in clinical bioimplantation are mainly Ti-6Al-4V alloys, but V is a toxic element to the human body. It accumulates in the bones, liver, kidney, spleen and other organs in the human body, and its toxicity exceeds that of Ni and Cr. At the same time, Al element can cause osteomalacia, anemia, and nervous system disorders. Therefore, non-toxic, better biocompatibility, and lower elastic modulus β-type titanium alloys have been studied since the 1990s, and non-toxic elements such as Nb, Ta, Zr, Sn and Mo have gradually become the main additions to the alloy. element. Among them, the Ti-Ta-Nb-Zr alloy system represented by the Ti-35Nb-5Ta-7Zr alloy in the United States and the Ti-29Nb-13Ta-4.6Zr alloy in Japan is characterized by its good biocompatibility and low mold The amount becomes the most promising biomedical alloy. However, even the bioalloy with the lowest modulus (Ti-29Nb-13Ta-4.6Zr: 55GPa) has a modulus much higher than that of human cortical bone, and a "stress shield" appears between the implant and human bone, resulting in The surrounding bone stress is absorbed, and the metal implant loosens and falls off. There are two main ways to solve the "stress shielding" problem of implants, one is to develop new alloy components to have better biocompatibility and lower modulus, and the other is to adopt a porous structure, because the porous The structure can further reduce the modulus of the alloy, making it closer to the real human bone. At the same time, the interconnected and appropriately sized pore structure is conducive to the ingrowth of surrounding cells and the growth of new bone, thereby enhancing the metal implant and human tissue. Combined, the service life of the metal implant is extended, and it can also provide a channel for the transmission of body fluids.

At present, the methods for preparing metal porous materials mainly include: powder metallurgy method, foaming method, fiber sintering method, plasma spraying method and so on. However, when these methods are used to prepare biomedical metal porous implant materials, there are problems such as the inability to personalize the implant design for individuals, the inability to flexibly control the pore structure, the inability to ensure the conductivity between the gaps, and the inability to better simulate and Issues such as the pore structure characteristics similar to the structure of human bone tissue.

Contents of the invention

In view of the problems of high toxicity of added elements and high elastic modulus in the existing biomedical metal implant materials, the purpose of the present invention is to provide a medical porous implant alloy material and a preparation method thereof.

A medical porous implant alloy material provided by the present invention is composed of an alloy containing four elements: Ti, Ta, Nb, and Zr, and contains several macropores with a diameter of 200 to 500 μm. On the walls of the macropores There are several small pores with a diameter of 5-30 μm; the porosity of the porous body is ≥30%.

Among them, the mass percentages of the four elements Ti, Ta, Nb, and Zr are 7-10% Ta, 28-32% Nb, 5-10% Zr, and the balance is Ti.

The present invention also provides a method for preparing the medical porous implant alloy material, comprising the following steps:

1) Design the three-dimensional model of the medical porous implant alloy material, convert it into a series of two-dimensional layered structure models, and import the obtained model into the electron beam rapid prototyping equipment, and set the processing parameters (temperature in the preheating stage, beam intensity in the preheating stage , forming stage temperature, forming stage beam intensity, electron beam scanning speed, powder coating thickness, etc.);

2) Using electron beam rapid prototyping equipment, in a vacuum environment, the pre-alloyed powder containing four elements of Ti, Ta, Nb, and Zr is melted and formed under the bombardment of the electron beam. After cooling, the remaining powder in the hole is cooled with high-pressure gas Blow out to obtain the medical porous implant alloy material.

Wherein, the three-dimensional model of the design of the medical porous implant alloy material in step 1) is a three-dimensional model obtained by obtaining the patient's medical photographic graphics through CT and MIR scanning technology, or using a three-dimensional drawing software (such as Auto CAD, etc.) A three-dimensional model of the implant is designed; the three-dimensional model includes settings for macropore size and porosity.

Wherein, in step 1), it is converted into a series of two-dimensional layered structure models. In order to perform surface grid processing on the three-dimensional model, the three-dimensional model is discretized into a series of two-dimensional layered models, usually along the Z direction into a series of level.

Among them, the setting of processing parameters in step 1) preferably sets the temperature of the forming base plate in the preheating stage to 700-800°C, the beam intensity in the preheating stage to 15-25mA, the temperature of the forming base plate in the forming stage to 750-850°C, and the beam intensity in the forming stage 30-40mA, electron beam scanning speed 6000-8000mm/s, powder coating thickness 0.05mm.

Wherein, in step 2), the pre-alloyed powder containing four elements of Ti, Ta, Nb, and Zr is melted and formed under the bombardment of electron beams, in order to put the pre-alloyed powder into the powder box of the electron beam rapid prototyping equipment, leveling and forming Base plate, calibrate the electron beam, turn on the electron beam rapid prototyping equipment, the pre-alloyed powder flows out of the powder box under the action of gravity, the scraper moves on the powder spreading plane, and spreads a layer of powder, and the electron beam is controlled by the program according to the model provided The information is sintered, and the pre-alloyed powder is sintered together under the bombardment of the electron beam, and bonded with the formed part below. This process is repeated, layer by layer, until the entire implant is sintered. During the forming process, under the premise of ensuring no powder blowing, the beam intensity should be reduced as much as possible and the scanning speed should be increased to reduce the molten pool, increase the solidification speed, and form a fine microporous structure on the hole wall.

Among them, the particle size of the pre-alloyed powder is preferably 80 μm to 100 μm.

The present invention also includes the application of the medical porous implant alloy material.

The medical porous implant material of the present invention has the following advantages:

(1) The medical porous implant material of the present invention does not contain any toxic elements, has a lower modulus and better biocompatibility.

(2) The medical porous implant material of the present invention has adjustable large pores of 200-500 μm and small pores of 50-100 μm on the hole wall. This pore structure is similar to the human bone structure, and the large-pore structure can effectively reduce the metal modulus. The small pores increase the surface area, making it easy for cells and bone growth factors to reach, fix on the surface, and grow along the surface or gaps of the small pores.

The method for preparing the medical porous implanted alloy material according to the present invention is an electron beam rapid prototyping method, which has the following advantages:

(1) Three-dimensional drawing software such as CT, MIR medical images or Auto CAD can be used to personalize the design of implant materials for different patients, so that an implant that is basically consistent with the shape of the replacement bone can be obtained, which is conducive to maintaining the same shape as the bone replacement. Matching of original organs.

(2) It has the characteristics of rapidity, accuracy and good at making complex shape entities.

(3) This method does not require molds during the design process, reducing manufacturing costs.

(4) The pore size, porosity, and connectivity inside the pores are the decisive factors for the way and quantity of bone ingrowth after the bone-like material is implanted in the body. The penetrability of the implant can promote the ingrowth of bone tissue and adjust the mechanical properties of the implant such as strength and modulus.

(5) The forming is carried out in a vacuum environment, which is conducive to the use of active metals, such as titanium alloys.

Description of drawings

Figure 1 is a macroscopic photo of a medical porous Ti-28Nb-10Ta-5Zr alloy with a macropore diameter of 1 mm.

Fig. 2 is a 1000 times scanning electron microscope photograph of a medical porous Ti-28Nb-10Ta-5Zr alloy with a macropore diameter of 1 mm.

Fig. 3 is a macroscopic photo of a medical porous Ti-32Nb-7Ta-5Zr alloy with a macropore diameter of 2 mm.

Fig. 4 is a 1000 times scanning electron microscope photograph of a medical porous Ti-32Nb-7Ta-5Zr alloy with a macropore diameter of 2 mm.

Detailed ways

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1 Preparation of a medical porous Ti-28Nb-10Ta-5Zr alloy with a macropore diameter of 1 mm

In this example, a medical porous Ti-28Nb-10Ta-5Zr alloy with a macropore diameter of 1 mm was prepared by using the electron beam rapid prototyping method. The specific steps are as follows:

1) First, use CAD software to build a 20×20×20mm three-dimensional model, the interior is a large hole structure with a diameter of 1mm, and perform surface mesh processing on the three-dimensional model to form an STL format file. According to the process requirements, use the software to discretize the three-dimensional model into a series of The unit of the CAD model is divided into 400 layers along the Z direction, that is, the thickness of each layer is 0.05mm. Import the layered model into the electron beam forming equipment, and input the processing parameters (preheating stage temperature, beam intensity, forming stage temperature, beam intensity, electron beam scanning speed, powder coating thickness, etc., see step 2 for specific requirements).

2) Screen the gas-atomized spherical Ti-28Nb-10Ta-5Zr pre-alloyed powder with a particle size of 80 μm to 100 μm. Put the alloy powder into the powder box, level the bottom plate of the electron beam forming equipment, after the electron beam is calibrated, vacuumize to 5×10-2Pa, and start forming the sample according to the model set in step 1). The forming process is divided into a preheating stage and a forming stage. The temperature of the forming base plate in the preheating stage is 700°C, the beam intensity in the preheating stage is 15mA, the temperature of the forming plate in the forming stage is 750°C, and the beam intensity in the forming stage is 30mA. The speed is 6000mm/s, and the powder coating thickness is 0.05mm. After forming, the sample is cooled to room temperature in the forming cavity and taken out, and the remaining powder in the hole is blown out with high-pressure gas.

The finally obtained medical porous Ti-28Nb-10Ta-5Zr alloy implant has a large pore diameter of 1mm, a small pore diameter of about 10-30μm on the pore wall, an overall porosity of 82%, and an elastic modulus of 5.36GPa. The macroscopic structure of the large pores is shown in Figure 1, and the microscopic structure of the small pores on the wall of the large pores is shown in Figure 2.

Example 2 Preparation of a medical porous Ti-32Nb-7Ta-5Zr alloy with a macropore diameter of 2 mm

In this example, a medical porous Ti-32Nb-7Ta-5Zr alloy with a macropore diameter of 2 mm was prepared by the electron beam rapid prototyping method, and the specific steps were as follows:

1) First, use CAD software to build a 20×20×20mm three-dimensional model. The interior is a large-pore structure with a diameter of 2mm. The surface grid of the three-dimensional model is processed to form an STL format file. According to the process requirements, the three-dimensional model is discretized into one A series of units divides the CAD model into 400 layers along the Z direction, that is, the thickness of each layer is 0.05mm. Import the layered model into the electron beam forming equipment, and input the processing parameters.

2) Screen the gas-atomized spherical Ti-32Nb-7Ta-5Zr alloy powder with a particle size of 80 μm to 100 μm. Level the bottom plate of the electron beam forming equipment, and after the electron beam is calibrated, put the metal powder into the powder box, vacuumize to 5×10-2Pa and start forming the sample according to the model set in step 1). The forming process is divided into a preheating stage and a forming stage. During the preheating process, the temperature of the forming base plate is 750°C, and the beam intensity is 25mA. During the forming process, the temperature of the forming base plate is 800°C, the beam intensity is 35mA, and the scanning speed of the electron beam is 8000mm/s. , The thickness of the powder coating is 0.05mm. After the structure is formed, it is cooled to room temperature in the forming cavity and taken out, and the remaining powder in the hole is blown out with high-pressure gas.

The finally obtained medical porous Ti-32Nb-7Ta-5Zr alloy has a large pore diameter of 2mm, a small pore diameter of 5-10μm on the pore wall, an overall porosity of 90%, and an elastic modulus of 3.53GPa. The macroscopic structure of large pores is shown in Figure 3, and the microscopic structure of small pores on the walls of large pores is shown in Figure 4.

Although the present invention has been described in detail with general descriptions and specific embodiments above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (7)

1. A medical porous implant alloy material, composed of an alloy containing four elements: Ti, Ta, Nb, and Zr, contains several porous bodies with a diameter of 200-500 μm macropores, and the walls of the macropores have several A small hole with a pore diameter of 5-30 μm; the porosity of the porous body is ≥30%; the mass percentages of the four elements of Ti, Ta, Nb, and Zr are: 7-10% Ta, 28-32% Nb, 5-10% Zr, the balance is Ti; The medical porous implant alloy material is prepared through the following steps: 1) Design the three-dimensional model of the medical porous implant alloy material, convert it into a series of two-dimensional layered structure models, and import the obtained models into the electron beam rapid prototyping equipment to set the processing parameters; 2) Using electron beam rapid prototyping equipment, in a vacuum environment, the pre-alloyed powder containing four elements of Ti, Ta, Nb, and Zr is melted and formed under the bombardment of the electron beam. After cooling, the remaining powder in the hole is cooled by high-pressure gas Blow out to obtain the medical porous implant alloy material; The processing parameters of step (1) are: the temperature of the forming base plate in the preheating stage is 700-800°C, the beam intensity in the preheating stage is 15-25mA, the temperature of the forming base plate in the forming stage is 750-850°C, the beam intensity in the forming stage is 30-40mA, The beam scanning speed is 6000-8000mm/s, and the powder spreading thickness is 0.05mm. 2. the method for preparing the described medical porous implant alloy material of claim 1, comprises the steps: 1) Design the three-dimensional model of the medical porous implant alloy material, convert it into a series of two-dimensional layered structure models, and import the obtained models into the electron beam rapid prototyping equipment to set the processing parameters; 2) Using electron beam rapid prototyping equipment, in a vacuum environment, the pre-alloyed powder containing four elements of Ti, Ta, Nb, and Zr is melted and formed under the bombardment of the electron beam. After cooling, the remaining powder in the hole is cooled by high-pressure gas Blow out to obtain the medical porous implant alloy material; The processing parameters of step (1) are: the temperature of the forming base plate in the preheating stage is 700-800°C, the beam intensity in the preheating stage is 15-25mA, the temperature of the forming base plate in the forming stage is 750-850°C, the beam intensity in the forming stage is 30-40mA, The beam scanning speed is 6000-8000mm/s, and the powder spreading thickness is 0.05mm. 3. the preparation method of medical porous implant alloy material as claimed in claim 2, is characterized in that, the three-dimensional model of the described design medical porous implant alloy material of step 1) obtains the patient's medical photography by CT, MIR scan technology The three-dimensional model obtained by digitizing graphics, or the three-dimensional model designed by using three-dimensional drawing software; the three-dimensional model includes the setting of macropore diameter and porosity. 4. The preparation method of medical porous implant alloy material as claimed in claim 2, characterized in that, step 1) described into a series of two-dimensional layered structure model, for carrying out surface grid treatment to three-dimensional model, the three-dimensional model It is discretized into a series of two-dimensional layered models along the Z direction. 5. the medical porous implant alloy material preparation method as claimed in claim 2, is characterized in that, step 2) the described pre-alloy powder that comprises Ti, Ta, Nb, Zr four kinds of elements melts under the bombardment of electron beam Forming, in order to put the pre-alloy powder into the powder box of the electron beam rapid prototyping equipment, level the forming base plate, calibrate the electron beam, start the electron beam rapid prototyping equipment, the pre-alloy powder flows out of the powder box under the action of gravity, and the scraper moves at Spread a layer of powder on the powder laying plane, and the electron beam is sintered according to the information provided by the model under the control of the program. The pre-alloyed powder is sintered together under the bombardment of the electron beam and bonded with the formed part below. This process Repeatedly, layer by layer, until the entire implant is sintered. 6 . The method for preparing the alloy material for medical porous implants as claimed in claim 5 , wherein the particle size of the pre-alloyed powders of Ti, Ta, Nb and Zr is 80-100 μm. 7. The application of the medical porous implant alloy material according to claim 1.