Manufacturing method capable of improving mechanical performance of thick 7050-T7451 aluminum alloy plate

Abstract

The invention provides a manufacturing method capable of improving mechanical performance of a thick 7050-T7451 aluminum alloy plate, and belongs to the technical field of metallurgy. The manufacturing method comprises the following technological steps that (1) thermal treatment is conducted; (2) quenching and straightening are conducted; (3) stir friction machining is conducted on the obverse side; and (4) stir friction machining is conducted on the reverse side, so that the thick 7050 aluminum alloy plate with the uniform microstructure and obviously refined crystal grains is obtained. The manufacturing method is a machining mode with the minimum hardness span formed after stir friction machining in the research process at present. Compared with a conventional manufacturing method, the manufacturing method has the advantage that a heat affected zone and a thermo mechanical affected zone of the plate are removed. Compared with a double-side stir friction machining method newly developed in the recent period, the manufacturing method has the advantages that the difference between precipitated phases of an obverse side stir zone and a reverse side stir zone is remarkably reduced, the harness value is remarkably increased, and the span is smaller than or equal to 10 HV. In addition, the hardness of the thick aluminum alloy plate manufactured through the manufacturing method ranges from 130.1 HV to 152.9 HV, the tensile strength of the thick aluminum alloy plate ranges from 466 MPa to 503 MPa, and the elongation of the thick aluminum alloy plate ranges from 30.6% to 31.2%.

Description

Technical field [0001] The invention belongs to the technical field of metallurgy, and specifically relates to a processing method for improving the mechanical properties of a 7050-T7451 aluminum alloy thick plate. Background technique [0002] 7050-T7451 (Al-Zn-Mg-Cu) aluminum alloy, also known as high-strength aluminum alloy, has the advantages of high specific strength, high toughness and corrosion resistance, easy processing and forming, low cost, easy recycling, and environmental friendliness. It is used in the aerospace industry It has been widely used. For decades, the application of aluminum and aluminum alloys has been challenged by titanium, titanium alloys and composite materials, but the status of high-performance aluminum alloy thick plates as the main load-bearing material has basically not changed. [0003] With the continuous development of modern technology, the new generation of aircraft puts forward higher requirements for materials. Advanced aircraft parts req...

AI Technical Summary

Problems solved by technology

However, the traditional friction stir processing method is greatly affected by the heat input and thermal cycle of the stirring equipment, and there is a thermomechanical affected zone (Thermo Mechanical Affected Zone, TMAZ) and thermal influence between the adjacent lap stirring zones (Stir Zone, SZ). (Heat Affected Zone, HAZ), and due to the coarse grain and certain directionality, the existence of heat affected zone and heat affected zone often become the weak area of ​​superplastic forming process

The newly developed double-sided friction stir processing method better compensates for the defects of the traditional friction stir processing method. It can eliminate the thermal-mechanical affected zone and the heat-affected zone, so that the uniformity of the structure can be solved, but the heat input of the reverse side processing makes the front side stir. The number of precipitates in the zone increases and the size is coarse, which affects the uniformity of mechanical properties

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