7056铝合金厚板组织和性能研究

Study of Mechanical Properties and Microstructure of 7056 AluminumAlloy Thick Plates

摘要:

通过金相显微镜、透射电镜和扫描电镜观察及x射线衍射织构测量与拉伸实验,研究了40mm厚7056合金厚板热轧态与时效后不同厚度层微观组织与力学性能。结果表明：热轧态厚板不同厚度层的组织有很大差别,表层第二相弥散,尺寸相对较小,中心层有粗大的第二相,分布集中。从表层到中心层,剪切织构减少,中心层变形织构最多,不同厚度层立方织构差别不大。固溶后表层再结晶织构增加,剪切织构减少,中心层变形织构增强。固溶时效后表层与中心层晶内均出现大量均匀细小的η’相,晶界处都出现不连续析出相与一定宽度的无沉淀析出带。40mm厚板(7056合金)最优固溶制度是470℃/3h,时效后表层屈服强度为605MPa,抗拉强度达628MPa；T/4层屈服强度626MPa,抗拉强度达643MPa；中心层屈服强度623MPa,抗拉强度达639MPa。

Abstract:

Tensile tests, optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were carried out to characterize the mechanical properties and microstructure of 7056 aluminum alloy plates, which were 40 mm thick by hot rolling. The results show that the microstructure of 7056 hot rolling plate is inhomogeneous in different layers. The second phase particles in surface distribute dispersively, and the size is relatively small, while are concentrated in the centre, and the size is relatively large. From surface to centre, The shear texture is gradually reduced. The content of deformation texture in the center layer is the largest, and the difference of cube texture in each layer is not significant. After solution treatment, the recrystallization texture increased and the shear texture decreased in the surface, and the deformation texture of the central layer increased. After aging, a large amount of homogeneous and fine η" phase appeared in the surface layer and the center layer, while discontinuous precipitates and a certain width of precipitation-free zone can be observed at grain boundaries. Optimal solution treatment of 40 mm thick 7056 plate is 470℃ for 3h. After aging, the yield strength of the surface layer is 605MPa and the tensile strength is 628MPa. The yield strength of T / 4 layer is 626MPa and the tensile strength is 643MPa. The yield strength of the center layer is 623MPa and the tensile strength is 639MPa.