【摘要】 测试了不同预析出处理条件下7050铝合金的拉伸性能和电导率,并采用光学显微镜、扫描电镜等手段观察了金相组织、第二相粒子以及断口形貌等特征,并在此基础上分析了强度、电导率以及断口形貌与微观组织演变之间的内在机制。结果表明,随着预析出温度的提高,基体内预析出形成的S、η平衡相逐渐减少而溶质原子数量增加,因而120℃,24h峰值时效形成的GP区、η’亚稳相数量相应增加,导致7050合金强度提高而电导率下降。可剪切的亚稳相和不可剪切的预析出平衡相对滑移位错的不同阻碍作用使得不同预析出处理条件下的断口形貌不同。更多还原

【Abstract】 Tensile properties and electrical conductivity of 7050 aluminum alloy in various pre-precipitation treatments were measured. On the basis of optical and SEM observations, the relation between strength, tensile fractography and microstructural evolution was clarified. The experimental results show that the fraction of equilibrium pre-precipitates in the matrix reduces gradually and the fraction of solute atoms increases with the rise of pre-precipitation temperature. Therefore, the number of meta-equilibrium precipitates at 120 ℃, 24 h artificial ageing increase, which led to higher strength and lower electrical conductivity of 7050 aluminum alloy. Shear-able metaequilibrium precipitates and non-shear-able equilibrium precipitates impose different dragging forces on sliding dislocations, which contributes to different tensile fractography.更多还原