Preparation method of novel Ti-xCu titanium alloy

Abstract

The invention relates to the field of novel titanium alloy manufacturing, in particular to a method for double-wire electric arc additive manufacturing of a Ti-xCu titanium alloy formed part. A double-wire electric arc additive manufacturing system is adopted, Ti and Cu elements are fed into a molten pool to achieve in-situ alloying by controlling the wire feeding speed of a designed TA1 welding wire and a designed pure Cu welding wire, and a novel Ti-xCu titanium alloy component can be obtained. Compared with a pure titanium component, the tensile strength and the microhardness of the Ti-xCu component added with the Cu element are remarkably improved.

Description

Technical Field

[0001] The invention relates to the field of novel titanium alloy manufacturing, and in particular to a method for manufacturing a Ti-xCu titanium alloy formed part by double-wire arc additive manufacturing. Background Art

[0002] At present, pure titanium, a low-cost medical metal material, is widely used in the manufacture of implantable devices. However, pure titanium has low strength, soft texture, easy deformation, poor load-bearing capacity, and poor corrosion resistance. After implantation in the human body, it is prone to loosening and failure caused by corrosion, which reduces the long-term stability and expected service life of the implant. Ti-xCu alloys have higher hardness, corrosion resistance and antibacterial properties than pure titanium, and are widely used in medical metal materials and aerospace fields. Arc additive manufacturing is a technology for manufacturing parts layer by layer. It has the advantages of high deposition efficiency, high material utilization and short preparation cycle. It has great advantages in the manufacture of small batches of complex components and can manufacture near-net-shape parts. Summary of the invention

[0003] The present invention provides a novel method for preparing a Ti-xCu titanium alloy formed part. The Ti-xCu alloy is manufactured by arc additive manufacturing, and the Ti and Cu elements are added into the molten pool to realize in-situ alloying by controlling the wire feeding speed of the designed TA1 welding wire and the pure Cu welding wire, so as to obtain a Ti-xCu alloy component.

[0004] The present invention is achieved through the following technical solutions:

[0005] A twin-wire arc additive manufacturing system is used to melt the TA1 wire and pure Cu welding wire using the GTAW (Gas Tungsten Arc Welding) heat source, and in-situ alloying is performed in the molten pool to prepare Ti-xCu alloy components. The specific steps include:

[0006] (1) Clean the surface of the TA1 substrate by mechanical grinding and chemical cleaning.

[0007] (2) The TA1 substrate is fixed on the fixture of the workbench, and the bottom of the substrate is cooled naturally. The wire feeding speed is designed according to the composition of Ti-xCu (x=4.5, 6.5, 8.5, 10). The GTAW equipment is used to optimize the process parameters, melt the TA1 wire and pure Cu welding wire, and stack them layer by layer to form a molded part of a set height. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Schematic diagram of Ti-xCu alloy parts manufactured by twin-wire arc additive manufacturing

[0009] Figure 2 Microhardness distribution of pure titanium and Ti-xCu components

[0010] Figure 3 Tensile strength and elongation of pure titanium and Ti-xCu components DETAILED DESCRIPTION

[0011] The embodiments of the present invention are further described below in conjunction with the accompanying drawings and specific examples:

[0012] The test base material involved in the present invention is a TA1 substrate, the test piece specification is 250×150×5mm, TA1 and ER-Cu are selected as the raw materials for deposition, and a double-wire tungsten inert gas shielded arc additive manufacturing technology is used to carry out a molded part deposition test on the TA1 substrate.

[0013] The main implementation steps are as follows:

[0014] 1. Before deposition, use 120-grit sandpaper to remove the oxide on the surface of the TA1 substrate, and use alcohol to wipe off the oil and dirt on the surface of the deposition area. After cleaning, carry out the deposition experiment in time to avoid the formation of a new oxide film.

[0015] 2. Set the corresponding deposition parameters in the control module: the wire feeding speed of TA1 is constant at 1500mm / min, the wire feeding speeds of ER-Cu corresponding to Ti-4.5Cu, Ti-6.5Cu, Ti-8.5Cu and Ti-10Cu are 28mm / min, 53mm / min, 71mm / min and 84mm / min respectively, the welding current is 120A, the welding power supply adopts pulsed DC, the welding speed is 150mm / min, the welding stroke is 200mm, the welding torch swing width is 8mm, the substrate is not preheated and the bottom is naturally cooled, and the argon (99.999%) gas flow rate of the fairing hood and the welding gun is 15L / min.

[0016] 3. Before deposition begins, place the substrate on the workbench, turn off the wire feeding, and allow the welding torch to travel empty without arcing to simulate the test.

[0017] 4. The arc was started on one layer of the substrate to start the first additive manufacturing process with a length of 200 mm and an inter-layer cooling time of 1 min.

[0018] 5. After the first layer is completed, move the welding torch to the arc starting point of the upper layer, and then carry out the additive manufacturing of the second layer, raising the welding torch 2mm for each layer.

[0019] 6. After the second layer of additive manufacturing is completed, repeat step 5 until the number of deposited layers reaches 20, and finally extinguish the arc to complete the additive manufacturing of the net shape part.

[0020] After obtaining the additive single wall, the test specimens were processed by wire cutting, and the specimens were ground and polished. First, the microhardness test of the polished specimens from bottom to top was carried out using a Vickers hardness tester (HMV-2T type), with a loading time of 15s and a load of 1.9N. The tensile specimens were cut in the longitudinal direction. The thickness of the polished tensile specimens was 1.2mm, and the surface of the tensile specimens was smooth without grooves. At room temperature, the tensile strength of the components was tested using an electronic universal material testing machine (DDL10 type), with a tensile speed of 1mm / min.

[0021] Figure 1 Schematic diagram of twin-wire arc additive manufacturing of Ti-xCu alloy parts. Figure 2 The microhardness distribution of the cross section of pure titanium and Ti-xCu components was tested. As the copper content increased, the microhardness of the components increased. The overall hardness of the Ti-8.5Cu components was greatly improved compared with pure Ti, reaching 345.6HV. 0.2 . Figure 3 The tensile strength and elongation of pure titanium and Ti-xCu components are shown. The Ti-10Cu component has the highest average tensile strength, reaching 910MPa, which is 141% higher than that of pure Ti, and the elongation is similar to that of pure Ti components.

[0022] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A method for preparing a novel Ti-xCu titanium alloy, characterized in that: By using an arc additive manufacturing system, Ti and Cu elements are added into the molten pool by controlling the wire feeding speed of the designed TA1 wire and Cu wire, and Ti-xCu alloy components can be obtained.

2. For the arc additive manufacturing system in step 1, a dual wire feeding mechanism is used, and the wire feeding speed is designed according to the composition of Ti-xCu (x=4.5, 6.5, 8.5, 10), and the TA1 wire and the Cu wire are melted and stacked layer by layer to form a molded part of a set height.

3. For the arc additive manufacturing system in step 1, a GTAW (Gas Tungsten Arc Welding) heat source is used, and the TA1 welding wire and the pure Cu welding wire are fed into the molten pool to achieve in-situ alloying to prepare Ti-xCu alloy components.

4. For the Ti-xCu components prepared in step 1, the tensile strength and microhardness of the Ti-xCu components after adding Cu element are significantly improved compared with those of pure titanium components.

5. For the arc additive manufacturing system in step 1, the welding current is 120A, the welding power supply adopts pulsed DC, the welding speed is 150mm / min, the welding stroke is 200mm, the welding torch swing width is 8mm, the substrate is not preheated and the bottom is naturally cooled, and the argon (99.999%) gas flow rate of the fairing hood and the welding gun is 15L / min.

6. Design the wire feeding speed for the composition of Ti-xCu (x=4.5, 6.5, 8.5, 10) in step 2. The TA1 wire feeding speed is always 1500 mm / min, and the ER-Cu wire feeding speeds corresponding to Ti-4.5Cu, Ti-6.5Cu, Ti-8.5Cu and Ti-10Cu are 28 mm / min, 53 mm / min, 71 mm / min and 84 mm / min, respectively.

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