Study On Heat Treatment Technics Of Ultra-high Strength Al-Zn-Mg-Cu Series Alloys

The preparation and heat treatment technics of nine kinds of aluminum alloys in Al-Zn-Mg-Cu series were systematically studied in this article. Combining with the microstructure observed by metallograph microscope and electron microscope, the effects of heat treatment on macroscopical mechanics properties, including strength,ductility ,fracture toughness and conductance, were investigated and analyzed. Through large numbers of tests, three results and four innovation points were got.1) Through properly adjusting components of the alloys, preparation technics and heat treatment project, the alloys got better general properties and grain-sizes than before.2) The new technics of compound solution largely enhanced solid solubility and heightened the overheat temperature with about 10℃.3) Integrating compound solution with two-peak-aging, new states of 7711T79 and 7055T78 were got. Through new heat treatment scheme (Solution:470℃/400min +480℃/2(min Aging :135℃/16h₁90℃/10min the tensile strength of 7711 reaches 778MPa, the jield strength of it arrived at 757MPa, and the extension ratio attains 11.0%. Further more, through another new heat...