Al-Zn-Mg-Cu-Sc-Zr-RE alloy capable of being used as ultrahigh-strength cast aluminum alloy and preparation method thereof

Abstract

The invention discloses an Al-Zn-Mg-Cu-Sc-Zr-RE alloy capable of being used as an ultrahigh-strength cast aluminum alloy and a preparation method thereof. In the alloy, Zn and Mg with higher content are adopted, Sc and Zr are compositely microalloyed, and trace rare earth elements Er and / or Yb are added, so that the aims of increasing an eutectic phase proportion, thinning a grain structure, suppressing dendritic crystal growth and changing an alloy solidification mode are fulfilled to reduce the heat cracking tendency of the alloy and obviously improve the casting performance of the alloy. The alloy comprises the following components in percentage by weight: 7.0 to 8.0 percent of Zn, 1.5 to 2.5 percent of Mg, 1.4 to 2.0 percent of Cu, 0.2 to 0.5 percent of Mn, 0.15 to 0.25 percent of Sc,0.10 to 0.20 percent of Zr, 0.1 to 0.3 percent of Er and / or Yb and the balance of Al. The as-cast alloy can achieve high toughness performance through long-time variable-temperature homogenization, enhanced solid solution treatment and aging treatment, can be used for producing an aluminum alloy casting with the yield strength of more than 500MPa and the elongation rate of more than 5 percent andcan be used as an alternate material for the ultrahigh-strength wrought aluminum alloy.

Description

technical field [0001] The invention discloses an Al-Zn-Mg-Cu-Sc-Zr alloy which can be used for producing ultra-high-strength aluminum alloy castings and a preparation method thereof, belonging to the technical field of high-performance casting aluminum alloy materials and processing thereof. technical background [0002] Ultra-high-strength aluminum alloy has the advantages of low density, high strength, and good thermal processing performance. It has become the main structural material in the aerospace industry, and its use in civil aircraft has reached more than 50% of the weight of structural materials. In recent years, with the rapid development of aerospace, shipbuilding, and weapon industries, the demand for ultra-high-strength aluminum alloys has also continued to expand. At present, high-strength and high-toughness aluminum alloys mainly include 2XXX and 7XXX series of traditional deformed aluminum alloys, as well as powder metallurgy aluminum alloys, spray-formed a...

AI Technical Summary

Problems solved by technology

Since the existing high-strength and tough aluminum alloys are mainly Al-Cu alloys, the ultimate tensile strength of the highest-strength ZL205A alloy is difficult to break through 500MPa. Compared with deformed aluminum alloys, there is still a problem of insufficient strength and toughness.

In recent years, domestic studies on the use of deformed aluminum alloys to prepare aluminum alloy castings have been frequently reported, but they are still in the stage of laboratory research, and most of them are concentrated in squeeze casting and semi-solid thixotropic deformation research. Due to the thermal processing of 7XXX series deformed aluminum alloys characteristics and high aging treatment process requirements, so there are many problems to be solved in the further research and application research promotion, especially for large and complex castings, which are brought by squeeze casting and semi-solid thixoforming technology. The problems of high cost and difficulty in process realization have become increasingly prominent. Therefore, ultra-high-strength cast aluminum alloy materials and casting forming processes that can replace deformed aluminum alloys have been developed to achieve casting instead of forging. For expanding the application range of ultra-high-strength aluminum alloys, has important practical significance

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