A processing method for improving the mechanical properties of 7050‑t7451 aluminum alloy thick plate

Abstract

The invention provides a processing method for improving the mechanical properties of 7050-T7451 aluminum alloy thick plates, which belongs to the field of metallurgical technology and includes the following process steps: (1) heat treatment; (2) quenching and straightening; (3) front friction stir processing; (4) Reverse friction stir processing to obtain a 7050-T7451 aluminum alloy thick plate with uniform microstructure and significantly refined grains. This invention is the processing method with the smallest hardness span after friction stir processing in current research; compared with traditional processing methods, it eliminates the heat-affected zone and heat-mechanical affected zone of the plate; compared with the recently developed double-sided friction stir processing method, it has a positive The difference in precipitated phase in the reverse stirring zone is significantly reduced, the hardness value is significantly increased, and the span does not exceed 10HV. In addition, the aluminum alloy thick plate prepared by the method of the present invention has a hardness of 130.1-152.9HV, a tensile strength of 466-503MPa, and an elongation of 30.6-31.2%.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular 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. has been widely applied. 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 has put forward higher requirements for materials. The parts of advanced aircraft have harsh service con...

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

Images