Aluminum alloy and its composite material non-vacuum semi-solid state vibration-rheological connection method

Abstract

The invention provides a method for anti-vacuum vibrating theological connecting aluminum alloy and its complex material. The invention is characterized in that: clamping aluminum alloy or complex material weldment on chucking appliance and placing medium temperature welding material on two pre-welding surface, heating weldment with temperature being 380-400 Deg. C, starting vibrating device after welding material fusion, the amplitude is 0.1-0.5 mm. The temperature during vibrating process is the same, and the vibrating time is 10-300 seconds. The temperature is increased to 450-520 Deg. C after vibration, and it is kept for 1-5 minutes. Then starting vibrating device again, the amplitude is 0.1-1 mm, stopping after 3-60 seconds, forcing constant pressure with pressure range being between 0.1-2 Mpa, keeping temperature for 5-30 minutes, and cooling. The invention is characterized by low cost, high efficiency and quality.

Description

(1) Technical field [0001] The invention relates to an aluminum-based composite material welding method. (2) Background technology [0002] Aluminum matrix composites stand out for their outstanding advantages such as low cost, easy preparation, good wear resistance, strong designability of performance and functions, etc., and become the mainstream of research on metal matrix composites. It has broad application prospects in thermal and wear-resistant parts, and is considered to be one of the most promising composite materials in the 21st century. However, poor weldability has become a serious obstacle to the practical application of this material. In order to obtain breakthroughs in the connection of aluminum matrix composites, many scholars at home and abroad have so far performed fusion welding (such as TIG welding, laser welding, electron beam welding, etc.) and solid phase welding (such as diffusion welding, instant welding) of aluminum matrix composites. Liquid phase...

AI Technical Summary

Problems solved by technology

[0005] (1) Physical compatibility problem: part of the solid SiC or Al in the liquid molten pool 2 o 3 It seriously affects the heat transfer and mass transfer process in the molten pool, so that the molten pool exhibits high viscosity, poor flow, and high sensitivity to defects such as pores, incomplete fusion, and incomplete penetration; the molten aluminum matrix composite material and the applied The filling material is difficult to mix, the dilution rate is low, and the molding is difficult; at the same time, the segregation of the reinforcing phase when the liquid metal solidifies destroys its original distribution characteristics and deteriorates the performance of the joint; in addition, when the linear expansion coefficient of the reinforcing phase and the matrix differ greatly , a large internal stress will remain in the joint during the heating and cooling process of welding

[0006] (2) Chemical compatibility problem: Some reinforcing phases (such as SiC) and the matrix Al are thermodynamically unstable in a large temperature range, and harmful interfacial reactions at high temperatures in welding are inevitable

[0013] (2) Improper control of the welding process will lead to the melting of the matrix, and the enhanced phase segregation in the diffusion zone; no enhanced phase layer remains in the brazing seam structure, which cannot maintain the original special structure and special properties of the base metal

This is not suitable for occasions with special performance requirements for joints, such as joints that need to maintain good anti-damping characteristics and dimensional stability, etc.

[0014] (3) The melting points of the aluminum alloy matrix and the reinforcement phase are very different. At the brazing temperature, the matrix part melts, but the reinforcement does not melt, resulting in stickiness of the brazing filler metal, poor fluidity, and wetting of the brazing filler metal on the base metal. Spreading is seriously hindered by the presence of solid reinforcement phase, adding some alloying elements and increasing the brazing temperature can be improved to some extent, but the temperature is too high and it is easy to cause overburning and erosion of the base metal, which brings a negative impact on the brazing process. come very difficult

[0020] (2) In the absence of an intermediate layer, there is a phenomenon of direct contact between the reinforcement phase and the reinforcement phase on the contact surface of the aluminum matrix composite, and it is difficult to achieve the diffusion connection between the reinforcement phases under the conditions of diffusion welding

[0024] While instantaneous liquid phase welding has more advantages, it also has some disadvantages: (1) The segregation of the reinforcing phase becomes the main problem of TLP welding of this material

Many scholars at home and abroad have solved this problem by choosing a thinner intermediate foil layer, but in terms of practical application, the efficiency is low and it is difficult to realize the project

(2) The instantaneous liquid phase welding temperature generally exceeds 550°C. At this temperature, the base metal will soften to varying degrees, which is a challenge for the composite material matrix

However, at present, a large number of welding work of aluminum matrix composite materials is still carried out in the laboratory, and the TLP welding process with more practical application significance still needs to make further efforts

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