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Organization and composition of this thesis tested by the mechanical properties at room temperature , conductivity test and superplastic testing , using optical microscope , X - ray diffraction , scanning electron microscopy , transmission electron microscopy , energy dispersive analysis , spray forming 7475 aluminum alloy injection into the organization and performance of the morphological and squeezed states , the heat treatment process and the superplastic extruded alloy , ultra high strength aluminum alloy design , continuous improvement and optimization of the heat treatment process parameters and improve the superplastic accumulated data , the main findings are as follows : full automatically controlled reciprocating spray forming technology Ф360 mm × 1200 mm 7475 aluminum alloy industrial specifications prepared by spray forming blank . Typical organization is equiaxed grain , macroscopic uniform particle size , the size is primarily in the 30 to 50 μm . The no significant macrosegregation organization , relative density of 97% . The σb 245.7MPa, δ 5.85 percent . After the hot extrusion , the tissue is more dense, and the second phase distribution is more uniform . The alloy strength 319.7MPa, elongation increased to 18.79% , increased by 45.5% than the casting of 7475 aluminum alloy strength , elongation increased by 25.3% . The spray forming 7475 aluminum alloy single - stage solution temperature of 480 ° C suitable solution time of 3h . Two - stage solution , the increase in the number of second phase back dissolved and recrystallized grains grow significantly did not occur , the alloy strength , elongation is reduced . The single-stage aging high strength can be obtained . 120 ℃ / 24h peak aging single-stage , σb reach 738MPa , δ was 9.0 % , 33.0% higher than casting 7475 aluminum alloy strength , elongation increased by 12.5% ??. With two aging temperature and aging time , the decline in alloy strength , elongation and conductivity improve . 115 ℃ / 6h 163 ℃ / 6h two-stage aging treatment , σb 640 MPa , δ of 12.3% , the conductivity of 43.2% IACS than T76 handle casting alloy strength increased by 20.5% , 11.8% increase in elongation , the conductivity increased by 8 %. RRA process to obtain excellent overall performance , σb 716MPa, δ is 10.3% , the conductivity of 43.3% IACS . The high temperature overaging significant decrease in strength, to improve the plasticity . 7475 alloy extruded spray forming superplastic tensile recrystallization at 516 ℃ . As the strain rate is lowered , the elongation increased . The strain rate of 8.33 × 10-4 s-1 , to obtain maximum elongation of 960% .
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