Method for preparing a heterogeneous metal composite structure for medical implantation

Patent metadata

Field	Value
Publication number	US-2025064591-A1
Application number	US-202418811762-A
Country	US
Kind code	A1
Filing date	Aug 21, 2024
Priority date	Aug 21, 2023
Publication date	Feb 27, 2025
Grant date	—

Abstract

Disclosed is a method for preparing a heterogeneous metal composite structure for medical implantation, including the steps of: step 1, preparing titanium alloy powder into a porous skeleton according to different printing strategies; step 2, filling magnesium after being melted into pores of the porous skeleton; and step 3, cooling a titanium-magnesium interpenetrating phase composite structure prepared in step 2 to room temperature, and covering a surface of the titanium-magnesium interpenetrating phase composite structure with a hydroxyapatite coating. In the present disclosure, a porous lattice dot-array structure of titanium alloy is used as a skeleton, and the skeleton pore is filled by pressureless infiltration of magnesium or hot isostatic pressure.

First claim

1 . A method for preparing a heterogeneous metal composite structure for medical implantation, comprising the steps of:
step 1, preparing, based on a selective laser melting technique or a laser powder bed fusion technique, titanium alloy powder ( 7 ) into a porous skeleton ( 2 ) according to different printing strategies, step 2, filling magnesium after being melted into pores of the porous skeleton ( 2 ), and step 3, cooling a titanium-magnesium interpenetrating phase composite structure prepared in step 2 to room temperature, and covering a surface of the titanium-magnesium interpenetrating phase composite structure with a hydroxyapatite coating, wherein in step 1, the porous skeleton ( 2 ) has a lattice dot-array structure; the lattice dot-array structure is a body-centered cubic dot-array structure, a closed tetragonal beam-0 type structure or a closed arc beam-0 type structure; the body-centered dot-array structure is a hexahedron with eight vertices as key nodes, which are connected to each other to form external beams, and centers of the six faces serve as nodes of internal beams, and the internal beams are connected to and combined with the external beams to form a body-centered cubic structure; the closed tetragonal beam-0 type structure is based on a face-centered lattice to construct diagonal X-beams, middles of which are fixed using straight columns, and a base configuration is constructed by mirroring 2-3 times, joints between the diagonal X-beams are at the face centers of each plane, and the closed tetragonal beam-0 type structure is built by regulating a total horizontal length a and a vertical length b; the closed arc beam-0 type structure is based on a quadrilateral, with four sides cut with circular arcs, constructing arc beams for circular arrays to establish the closed arc beam-0 type structure, in which a horizontal arc diameter C 1 and a vertical arc C 2 are used as variable parameters to regulate the porosity of the closed arc beam-0 type structure; and by printing multiple lattice dot-array structures for different impact conditions and filling the same according to different stress regions of a pelvis, the closed arc beam-0 type structure is arranged in a sacral region; the body-centered cubic dot-array structure is arranged in an acetabular region; and the closed tetragonal beam-0 type structure is arranged in an iliac region, for connecting the sacral region and the acetabular region.

2 . The method for preparing a heterogeneous metal composite structure for medical implantation according to claim 1 , wherein in step 1, the porous skeleton ( 2 ) is prepared using the selective laser melting technique by the following specific method: purging, before printing, a material molding chamber of a selective laser melting device ( 6 ) with high-purity argon gas until oxygen content in the molding chamber is less than 0.1%, preheating a print substrate to 200° C., ensuring the dimensional accuracy for printing the porous skeleton ( 2 ), continuously printing the titanium alloy powder ( 7 ) with a median diameter of 35 μm in layers using the selective laser melting technique under the conditions of a laser power of 100 W, a laser scanning speed of 1200 mm/s, and a layer thickness of 30 μm.

3 . The method for preparing a heterogeneous metal composite structure for medical implantation according to claim 2 , wherein in step 2, the specific method for filling magnesium after being melt into pores of the porous skeleton ( 2 ) is as follows: placing the printed porous skeleton ( 2 ) on a stainless steel mold ( 3 ), placing a magnesium block ( 1 ) on the porous skeleton ( 2 ) in a smooth manner, and placing the stainless steel mold ( 3 ) on a fixing apparatus ( 4 ) in a graphite resistance furnace ( 5 ), to complete the preparatory work before the infiltration, wherein it is ensured that an actual height of the stainless steel mold ( 3 ) is higher than a plane of the magnesium block ( 1 ), the graphite resistance furnace ( 5 ) is heated to 800° C. by heating in the flow of argon for 10 min, during which, the molten magnesium block ( 1 ) flows into the pores of the porous skeleton ( 2 ) by its own gravity in the absence of external loads, and is cooled in the graphite resistance furnace ( 5 ) to complete the infiltration process.

4 . The method for preparing a heterogeneous metal composite structure for medical implantation according to claim 1 , wherein in step 1, the specific method for preparing the porous skeleton ( 2 ) by using laser powder bed fusion technique is as follows: processing titanium alloy powder ( 7 ) with a median diameter of 35 μm by adopting the laser powder bed fusion technique with a laser powder bed device ( 11 ) with process parameters of a scanning speed of 1,200 mm/s and a laser power of 155 W, reducing, during the scanning process, a thermal stress between two adjacent layers by using a sawtooth pattern, and alternating a scanning angle by 90° on a previous layer.

5 . The method for preparing a heterogeneous metal composite structure for medical implantation according to claim 4 , wherein in step 2, the specific method for filling magnesium after being melt into pores of the porous skeleton ( 2 ) is as follows: placing the prepared porous skeleton ( 2 ) in an alumina ceramic mold ( 10 ), evenly sprinkling the magnesium powder ( 9 ) inside pores of the porous skeleton ( 2 ), allowing the magnesium powder ( 9 ) to be fully filled into internal pores of the porous skeleton ( 2 ) by means of mechanical vibration, smoothly placing the alumina ceramic mold ( 10 ) in a hot isostatic pressing sintering furnace ( 8 ), vacuuming the hot isostatic pressing sintering furnace ( 8 ) and introducing argon gas, mixing the porous skeleton ( 2 ) and the magnesium powder ( 9 ) using a hot isostatic pressing process, and heating the hot isostatic pressing sintering furnace ( 8 ) in an argon environment in the pressure of 150 Mpa for 4 h to 900° C., heating 150 MPa pressure for 4 hours, the magnesium powder ( 9 ) being melted during the heating, and being closely adhered to the porous skeleton ( 2 ) under the pressure and temperature.

6 . The method for preparing a heterogeneous metal composite structure for medical implantation according to claim 3 , wherein in step 3, the specific method for covering a surface of the titanium-magnesium interpenetrating phase composite structure with a layer of hydroxyapatite coating is as follows: preparing the hydroxyapatite coating using an electrophoretic deposition method;
using the prepared titanium-magnesium interpenetrating phase composite structure as a negative electrode, and an inert electrode graphite sheet as a positive electrode, with two pole sheets of negative electrode and positive electrode kept parallel and a distance between the negative electrode and the positive electrode being at 20 mm, vertically inserting the titanium-magnesium interpenetrating phase composite structure into a quartz glass beaker with an HA suspension, adding 2% of a volume fraction of concentrated nitric acid as an electrolyte, adjusting a pH value with ammonia to stabilize the pH value at the range of 4-6, performing electrolytic deposition under a constant-voltage mode for a certain period of time under a set voltage, covering the surface of the titanium-magnesium interpenetrating phase composite structure as the negative electrode by the hydroxyapatite coating during deposition, closing a power source after the surface of the titanium-magnesium interpenetrating phase composite structure is completely covered with the hydroxyapatite coating, and taking out a sample for drying.

7 . The method for preparing a heterogeneous metal composite structure for medical implantation according to claim 5 , wherein in step 3, the specific method for coveri

Assignees

• Univ Jilin

Inventors

• Yu Zhenglei
• Xin Renlong
• Chi Haojie
• Gao Delong
• Xu Zezhou
• Guo Yunting
• Ma Long
• Yang Yanan
• Sha Pengwei
• Wang Jincheng
• Zhao Xin
• Liu He

Classifications

• B22F7/002

  of porous nature · CPC title

• B22F10/28 Primary

  Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] · CPC title

• B22F10/36

  of energy beam parameters · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• A61F2002/30985

  using three dimensional printing [3DP] · CPC title