【摘要】 采用SEM、OM、拉伸试验(室温/高温)、弯曲试验和晶间腐蚀试验等测试方法,对添加不同含量稀土元素镧的Al-Mg-Si-Mn合金组织、机械性能及耐腐蚀性能等进行研究,分析稀土元素镧对合金机械和耐腐蚀性能的影响。结果表明,随La元素的添加,合金的铸态组织逐渐细化,第二相形貌得到了改善,同时减薄了该合金型材粗晶区厚度,提高了Al-Mg-Si-Mn合金的机械性能和耐腐蚀性能。当La添加量为0.2%(质量分数)时,晶粒细化效果最好,型材粗晶区最薄;La质量分数大于0.2%时,过量的La形成的初生相与合金晶粒细化剂中的Ti相互作用,减少了异质形核核心的数量,导致晶粒粗化现象,降低了合金的机械性能和耐腐蚀性能。更多还原

【Abstract】 The microstructure, mechanical properties and corrosion resistance of Al-Mg-Si-Mn alloy with different La contents were studied by SEM, OM, tensile test(normal temperature/high temperature), bending test and intergranular corrosion test, and the effects of rare earth element La on the mechanical and corrosion properties of the alloy were analyzed. The results show that with the a ddition of La,the as-cast microstructure of the alloy is gradually refined, the morphology of the second phase is improved, the thickness of the c oarse grain zone of the profiles is reduced, and the mechanical properties and corrosion resistance of Al-Mg-Si-Mn alloy are improved. When La content is 0.2 wt%, the grain refinement effect is the best, and the coarse grain zone is the thinnest. When La content is greater than 0.2 wt%,the primary phase formed by excessive La interacts with the grain refiner Ti in the alloy, which reduces the number of heterogeneous nucleation cores, leads to grain coarsening phenomenon, and degrades the mechanical properties and corrosion resistance of th e alloy.更多还原