Research On New Type Of Ultra High Al-Zn-Mg-Cu Alloy

With the development of high technology fields of aeronautics and astronautics,requirements for the property of ultra high strength aluminum alloy to the higher.Howerver,conformance to requirements mainly is Al-Zn-Mg-Cu alloy.With the Zn?Mg?Cu element content increase in a certain range,the strength of Al-Zn-Mg-Cu alloy can improve.Howerver,when the Zn content reaches 11%(wt),the content of Mg and Cu can not reach 3%in the reported news,the purpose of this article is to explore the property of ultra high Al-Zn-Mg-Cu alloy,which is based on the Zn content of 11%,the content of Cu and Mg in excess of 3%,this is important for developing better property ultra high Al-Zn-Mg-Cu alloy.The laboratory utilizes water-cooled copper casting and semicontinuous casting to produce several ultra high Al-Zn-Mg-Cu alloy,which Zn content is 11%,Mg content reaches 5%,Cu content reaches 4%,which utilizes optical microscopy?scanning electron microscopy and energy disperse spectroscopy?differential thermal analysis?mechanical testing and some other means to research the foundry technology?rolling technology?as-cast structure and microstructure after heating treatment.microstructure and property of plates after heating treatment.The main results are as follows:(1)Adopting small water-cooled copper equipment with controlling the rate of the liquid lever produces high alloy content of Al Zn Mg Cu ingot casting with the size 200mm×120mm×36mm,the quality of ingot casting is preferably.(2)The over burnt temperature of three ultra high Al-Zn-Mg-Cu alloy ingot casting is 475 ? about,they have a large amount of residual phase after 465?×48h homogenization treatment;the ingots after medium temperature pretreatment,they can be rolled into plates with 10%-20%reduction rate;the over burnt temperature of plates is also 475? about,the residual phase can not be eliminated after solution treatment.(3)The solubility of alloying element of three ultra high strength aluminum alloy plates(Al-11Zn-5Mg-2.5Cu-0.12Zr(E1 alloy).Al-11Zn-5Mg-2.5Cu-0.12Zr-1Mn-0.3Cr(E2 alloy)?A1-11Zn-5Mg-4Cu-0.12Zr(E3 alloy))reach the limit after 465? ×30min solution treatment,harding and 120?×24h peak aging treatment;the strength of extension?yield strength?ductility of E1?E3 plate is634.739MPa?636.177Mpa;606.504MPa?601.883MPa;4%?6%.The strength of extension?yield strength?ductility of E3 plate at 250?is 350.774MPa;333.736MPa;4%.Based on 120?×24h aging then 300?×6h aging,The strength of extension?yield strength?ductility of E1 and E3 plate at 250? is 194.202MPa?189.042MPa;169.153MPa?148.262MPa;11.36%?11.56%?...