The Effect Of Heat Treatment Processes On Microstructures And Properties Of The Spray-deposition Ultrahigh Strength Aluminum Containing Sc

7000 series Al-Zn-Mg-Cu alloys, known as ultrahigh strength aluminum alloys, are widely used as structural parts on airplanes, space shuttles, military industry and so on, for some of their valuable properties such as high specific strength and stiffness, good processing ability, corrosion resistance and split tenacity, but its short comings is mainly low structural stability. In order to advancing ultrahigh strength aluminum alloy, this paper focused on modern ultrahigh strength aluminum alloy development, Aimed at the Natural Science Foundation of Inner Mongolia autonomous region and the use of target for the service conditions of 100~℃~ 300℃, added Sc and Zr as additional alloying elements, the effects of elements and heat treatment on microstructure, mechanical properties and structural stability.This article adopt Al-12Zn-2.4Mg-1.1Cu-0.3Sc-0.2Zr-0.3Ni alloy Sprayed deposition ultrahigh strength aluminum alloy, hardness testing and differential thermal analysis, study the effect of heat treating regime on mechanical property and micro-structure of the alloy in virtue of OM, SEM, TEM and XRD diffraction analysis. The results of studies show that:The diameter of the circular sprayed-power is about 3~15μm and the as-deposited alloy was composed of equiaxial grains with the size of 15μm; After annealing treatment the alloy composed of fine-grain equiaxial grains with the size of 15μm and its hardness is between 57 ~ 60 HRB ; The hardness of as-extrusion after solid-solution treatment under the temperature of 470℃, 480~℃and 490~℃for 0 ~ 2h value of between 61 ~ 67HRB; the organizations of the as-deposited and the as-extrusion containing Sc, Zr maintain good thermal stability. The optimal homogenization techniques was homogenizing 12 hour at 460~℃and the hardness of the as-extrusion after solution treatment at 480℃/0.5h value of 66.68 HRB.The Solidification process of spray deposition, the Primary A13(Sc, Zr) precipitates with LI2 structure formed in experimental alloys which size in the 100~200nm. Hoof-like secondary Al3(Sc,Zr) precipitates with the structure of LI2 formed from a(Al) matrix of the as-extrusion alloy a(Al) matrix after ageing at 480~℃/ 2h +120℃/24h.The second Al3(Sc,Zr) precipitates did not grow up and its diameter is 7~12nm.The peak profiles of the Rockwell hardness of the alloy after 480~℃/2h solution treatment then ageing treatment under the temperature of 110℃~150~℃shows for"double-peak"characteristics;the peak hardness of the maximal after 480~℃/ 2h solution treatment then aging treatment at 110~℃/ 8h is 73.22HRB;the interaction ofη′phase and little G.P zone leading to the hardness 67.1HRB of the alloy at ageing treatment at 120℃/24h.