MICRO-REGION SEMI-SOLID ADDITIVE MANUFACTURING METHOD

Abstract

Disclosed is a micro-region semi-solid additive manufacturing method, where rod-shaped materials are used as consumables, and heating modes such as a high-energy beam, an electric arc, a resistance heat, or the like are applied to the front end of the consumables to enable the front end to be in a semi-solid state in which the solid-liquid two phases coexist; at the same time, the rotational torsion and the axial thrust applied on the consumables have powerful effects such as shearing, agitation and extrusion, that is, the mold-free semi-solid rheoforming is performed. The consumable is transmitted to the bottom layer metal continuously in this manner to form metallurgical bonding, the stacking process is repeated according to a planned route obtained after discretization slicing treatment, and then an object or a stack layer in a special shape can be formed.

Claims

1. A micro-region semi-solid additive manufacturing method, wherein consumable materials are manufactured with rod or strip shaped materials as additives, and are hereinafter referred to as consumables; during operation, a claw drives the consumables to rotate at a speed of 200-10000 rpm and an axial thrust of 10-2000 N is applied to the consumables, and the heat source is used to heat the front end surface of the consumables to a liquid or semi-solid state; in the subsequent cooling and solidification process, the hot metal at the end of these consumables undergoes agitation and extrusion under the action of the axial thrust, rotational torsion and the counter-acting force of substrate or stack layers, to form a mold-free semi-solid rheological processing metal structure; the consumables are uniformly pushed forward at a consumption speed of 0.1-2 m/min and are moved at a speed of 0.1-4 m/min based on a moving path generated by the discrete sections to form continuous stack layers, and the stacking process is repeated to form a molded body; and the heat source comprises a laser beam, an electron beam, a plasma beam, an electric arc, a resistance heat, an induction heating or flame.

2. The semi-solid additive manufacturing method according to claim 1, wherein the electric arc is TIG, MIG or CMT.

3. The semi-solid additive manufacturing method according to claim 1, wherein a consumable form is rod or strip shaped materials, and cross-section shape is a solid circle, a hollow circle, a rectangle, or a polygon; one or more consumables are arranged side by side; the length of each consumable is 5-600 cm, and the consumables are used one by one; and the laser spot shape is a circular spot, an elliptical spot, a rectangular spot or a multi-spot.

4. The semi-solid additive manufacturing method according to claim 1, wherein an inclination angle of the consumable between the centerline of the consumable and the stack layer is 45-90, and the inclination direction is opposite to the moving direction of the consumable; the self-moving mode of the consumable is rotation or plane reciprocating motion; and the laser acts on the front side of the moving direction of the consumable and opposites to the consumable, and the angle of the laser and the stack layer is 5-60.

5. The semi-solid additive manufacturing method according to claim 1, wherein the upper and lower vibrations are added to the consumables to enhance the forging effect, wherein the vibration frequency is 1 Hz to 1 kHz, and the vibration amplitude is 0.1-1 mm.

6. The semi-solid additive manufacturing method according to claim 1, wherein high energy beam heat sources such as the laser and the electron beam work in a scanning heating mode, and the scanning frequency is 1 Hz to 5 kHz.

7. The semi-solid additive manufacturing method according to claim 1, wherein one or several combination external fields of current, magnetic field and ultrasound are simultaneously applied to the consumables to enhance the control effect of metallographic structure and performance.

8. The semi-solid additive manufacturing method according to claim 1, wherein in the additive manufacturing process, reinforced composite materials or functionally graded materials are prepared by simultaneously injecting alloy powder having a size of 20 nm to 500 m, reinforced particles, whiskers or short fibers into a V-shaped opening between the consumable and the stack layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a schematic diagram showing the principle of a micro-region semi-solid additive manufacturing method by using a laser as a heat source and driving consumables to vibrate up and down;

[0023] FIG. 2 is a local enlargement schematic diagram showing the principle of a micro-region semi-solid additive manufacturing method by using a laser as a heat source;

[0024] FIG. 3 is a schematic diagram showing the principle of a micro-region semi-solid additive manufacturing method by using TIG as a heat source;

[0025] FIG. 4 is a schematic diagram showing the principle of a micro-region semi-solid additive manufacturing method by using MIG as a heat source;

[0026] FIG. 5 is a schematic diagram showing the principle of particle reinforced composites preparing and micro-region semi-solid laser additive manufacturing;

[0027] FIG. 6 is a schematic diagram showing the principle of manufacturing the laser micro-region additive for the lateral reciprocating motion of rectangular consumables;

[0028] FIG. 7 is a comparison of the microstructure characteristics of semi-solid laser additive manufacturing: a) stainless steel original structure, and b) stainless steel semi-solid laser additive structure; and

[0029] FIG. 8 is a schematic diagram showing the surface and cross section of a single stack layer in a micro-region semi-solid additive manufacturing method.

DETAILED DESCRIPTION

[0030] Specific embodiment 1: the consumable material of this embodiment is 304 stainless steel round rod with a diameter of 5 mm, the substrate is Q235 low carbon steel. The angle between the consumable material rod and the stack layer is 75, the angle between the laser beam and the stack layer is 15, the laser power is 4 KW, and the laser focusing spot is rectangular and has a size of 6 mm1 mm.

[0031] The specific forming process includes the following steps: [0032] 1. Establish a 3D model of the metal parts, complete the slicing process by software and generate a machine processing path; [0033] 2. Remove the oxide film and dirts on the surface of the substrate and consumables; [0034] 3. Arrange the relative positions of the consumables, the substrate and the laser according to the settings, fasten the substrate, and use the three claws with water-cooling function to catch the consumables; [0035] 4. Turn on the power to make the three claws to drive the rod-shaped consumables to rotate, with the rotation speed of 800 n/min, and check the coaxiality and roundness deviation of the rotation of the consumables; [0036] 5. Open the inert gas protection, with the flow rate of argon gas of 30 L/min, and the diameter of the nozzle of 10 mm; [0037] 6. When the consumable rod rotates, it moves downwardly and squeezes the substrate, and the three claws apply auxiliary upper and lower vibration and axial thrust to the consumables while rotating, with the thrust of 200 N; [0038] 7. When the laser is turned on, the moving mechanism is started, and the moving mechanism moves at a running speed of 0.6 m/min according to the planned processing path, and the additive manufacturing process is implemented; and [0039] 8. Repeat the stacking process of step 7 to finally obtain the stack body, and perform the remaining processing and detection on the stack body.

[0040] FIG. 7 is a comparison of the 304 stainless steel forming structure and the consumable rod original structure of this embodiment. FIG. 7(a) is the original structure of the 304 stainless steel rod consumable, mainly composed of large pieces of primary austenite, and the grain boundary morphology is mainly flat. FIG. 7(b) shows the micro-region semi-solid laser forming structure. The primary austenite grains form a specific spherical or pellet shape under intense stirring and friction, and the grain size is finer. The bright part between spherocrystals is not a grain boundary in the conventional sense, but an extremely fine liquid phase hardened structure, so that it is almost impossible to distinguish its morphology under an optical microscope.

[0041] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that: the consumable materials are two metal rods with a diameter of 3 mm arranged side by side, and other steps and parameters are the same as those in specific embodiment 1.

[0042] Specific embodiment 3: as shown in FIG. 3, this embodiment differs from specific embodiment 1 in that: the heat source is Tig, the angle between the welding gun and the stack layer is 55, the diameter of the consumable rod is 4 mm, the angle between the consumable rod and the stack layer is 60, the current is 200 A, the processing speed is 0.3 m/min, the axial thrust of the consumable materials is 100 N, and other steps and parameters are the same as those in specific embodiment 1.

[0043] Specific embodiment 4: as shown in FIG. 4, this embodiment differs from specific embodiment 1 in that: the heat source is Mig, the angle between the welding gun and the stack layer is 55, the angle between the consumable rod and the stack layer is 60, the current is 300 A, the processing speed is 0.4 m/min, the axial thrust of the consumable materials is 100 N, and other steps and parameters are the same as those in specific embodiment 1.

[0044] Specific embodiment 5: as shown in FIG. 6, this embodiment differs from specific embodiment 1 in that: the consumable materials are rectangular strips with a section size of 10 mm3 mm, and the self-moving mode of the consumable materials is transverse mechanical reciprocating motion, with the reciprocating frequency of 100 Hz, the amplitude of 0.8 mm, the laser power of 6 KW, and the processing speed of 0.4 m/min.

[0045] Specific embodiment 6: as shown in FIG. 5, this embodiment differs from specific embodiment 1 in that: Both the consumable rod and the substrate are 6061 aluminum alloy, the laser power is 6 KW, the moving speed of the consumable materials is 0.4 m/min, and the axial thrust of the consumable materials is 50 N, and during the forming process, 320 mesh SiC reinforced particles are injected into the angle between the consumable materials and the stack layer to prepare particle reinforced aluminum matrix composite materials with a volume fraction of 25% added. Other steps and parameters are the same as in specific embodiment 1.

[0046] SiC reinforced aluminum matrix composite materials prepared by the micro-region semi-solid additive manufacturing method have a full density, the particle and matrix interface are well bonded, the elastic modulus strength is increased by 27%, and the strength is increased by 18%.

[0047] The above embodiments are merely further description of the present invention, and specific embodiments of the present invention are not limited to the description. A series of methods derived from simple derivation and modification should be considered as belonging to the scope claimed in the present invention without departing from the concept of the present invention.