【摘要】 采用X射线衍射仪、扫描电镜以及光学显微镜等手段对等径角挤压（ECAP）变形前后7A60铝合金多元合金相的演化进行研究。结果表明,轧制态7A60铝合金内部主要存在MgZn₂、Al₂Cu相,等径角挤压工艺可以明显地碎化合金内部的第二相,改善其分布的均匀性;随着变形道次的增加,基体中粗大第二相沿剪切方向发生明显碎化,第二相发生回溶,四道次ECAP变形后第二相碎化成球状,尺寸由5²0μm碎化到1μm左右;初始态7A60铝合金抗拉强度为305MPa,随着变形道次的增加,合金的强度增强,四道后7A60铝合金的抗拉强度为492MPa;拉伸断口表现为韧性断裂,第二相对韧窝的形状和尺寸起决定性作用。更多还原

【Abstract】 The evolution of the multicomponent alloy phase in 7 A60 aluminum alloy before and after ECAP processing were studied by means of X-ray diffraction,scanning electron microscopy(SEM)and optical microscopy(OM).The results revealed that MgZn2 and Al2 Cu were mainly phase in 7 A60 aluminum alloy.ECAP could significantly break the coarse secondary phases and improved the unifor-mity of its distribution.The secondary phase was refined in the shear direction and the main second phase(MgZn2)dissolved into the aluminum matrix with the deformation pass increasing.After four passes,globularization of secondary phase was greatly promoted with the grain size decreasing from 5—20μm to about 1μm.With the increase of deformation pass,the strength of the alloy was enhanced,the tensile strength from 305 MPa in the initial state was up to 492 MPa after 4 passes.The tensile fracture was manifested as a ductile fracture,and the secondary phase played a decisive role to the shape and size of the dimple.更多还原