10%冷变形对7A85铝合金时效微观组织性能的影响

采用半连续铸造工艺制备了7A85铝合金铸锭、挤压工艺制备截面尺寸为50mm×300mm的挤压带板,并对挤压带板进行固溶处理、10%冷压缩处理以及120℃人工时效处理。通过TEM观察、力学性能测试等手段,研究了10%冷变形对7A85铝合金时效微观组织演变规律的影响。结果表明,固溶处理后,10%冷变形处理使合金中产生大量位错,从而提高了合金强度;时效初期,10%冷变形处理的7A85合金中析出相数量较未冷变形处理7A85合金明显增多,起到一定预时效作用;时效末期,10%冷变形处理的7A85铝合金析出相与位错数量均高于未冷变形处理的7A85铝合金,使得合金抗拉强度与屈服强度提升,而伸长率降低。

Effect of 10%Cold Deformation on Aging Microstructure and Properties of 7A85 Aluminum Alloy

7 A85 aluminum alloy ingots were prepared by semi-continuous casting process,and extruded strip plate with section size of 50 mm×300 mm was prepared by extrusion process,followed with solution treatment,10%cold compression treatment and artificial aging treatment at 120℃.The effects of 10%cold deformation on the aging microstructure of 7A85 aluminum alloy were investigated by means of TEM and room temperature testing.The results indicate that after solution treatment,a large number of dislocations are induced by 10%cold deformation treatment,thus improving the strength of the alloy.At the initial stage of aging,the amounts of precipitates in the 7A85 alloy with 10%cold deformation treatment is significantly higher than that of ones without cold deformation treatment,which plays a certain role in pre-aging.At the end of aging,the amounts of precipitates and dislocations in 7A85 aluminum alloy treated by 10%cold deformation are higher than that of ones without cold deformation treatment,leading to the enhancement of tensile strength and yield strength as well as reduction of the elongation.