A kind of preparation method of high-strength weldable al-zn-mg-mn-sc alloy

Abstract

The invention relates to a trace -scandium alloyed Al-Zn-Mg-Mn-Sc alloy and a preparation method thereof. The alloy comprises the following components in percentage by mass: 5.2-5.6% of Zn, 1.8-2.2% of Mg, 0.2-0.4% of Mn, 0.26-0.38% of Sc and the balance of Al. The method for preparing the aluminum alloy is implemented by adding an Al-Sc interalloy in the traditional Al-Zn-Mg-Mn-Sc alloy smelting process. The alloy has reasonable component proportioning and simple preparation technique, and the microalloying action of the Sc element obviously refines the crystal grains of the Al-Zn-Mg-Mn-Sc alloy and enhances the strength of the alloy. Fine uniformly-dispersed Al3Sc particles are precipitated from the matrix in the alloy welding process to violently knock the dislocation and subboundary, thereby improving the weldability of the alloy and greatly enhancing the welding strength coefficient of the alloy. The alloy can be used as an aerospace structural material.

Description

technical field [0001] The invention belongs to the technical field of aluminum-based alloys, in particular to an Al-Zn-Mg-Mn-Sc alloy and a preparation method thereof. Background technique [0002] Al-Zn-Mg-Mn alloy has the characteristics of high strength, good weldability, and small specific gravity, and has been widely used in the aerospace field. Al-(5.2-5.6) is used in the structural parts of my country's aerospace field that bear high loads, such as the body support and frame of the new generation of vehicles, the thermal control cover of the orbit control engine, the metal sealed cabin of the satellite and spacecraft structure, etc. Zn-(1.8~2.2)Mg-(0.2~0.4)Mn alloy. [0003] In the long-term application practice, aerospace users have reported that the biggest shortcomings of Al-Zn-Mg-Mn alloys are: ①The strength is low, and the maximum tensile strength of the alloy sheet is about 500MPa, which cannot meet the high load and light weight of the new generation of aerosp...

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Problems solved by technology

[0003] In the long-term application practice, aerospace users have reported that the biggest shortcomings of Al-Zn-Mg-Mn alloys are: ①The strength is low, and the maximum tensile strength of the alloy sheet is about 500MPa, which cannot meet the high load and light weight of the new generation of aerospace vehicles. ② Welding is easy to soften, making the heat-affected zone near the weld the weakest link of the structure, and structural reinforcement of the welded components is required. Welding softening also causes large welding deformation, which affects the dimensional stability of the welded structure

At present, the widely used method is microalloying with transition metals Zr, Cr and / or rare earth elements Ce, La, Yb, etc., but the effect of improving the strength and weldability of the alloy is not obvious, and it is difficult to meet the needs of aerospace users.

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