【摘要】 通过亚快速凝固技术提高铸造2A97合金中Cu的溶解度,从而提高合金强度。对不同Cu含量Al-Li合金进行力学性能研究,借助于OM、SEM、EDS等方法进行显微组织分析。结果表明,随Cu含量增加,合金强度先升高后降低,以脆性断裂为主,合金主要强化相θ′、S′和σ相分布和比例发生变化,引起均匀化处理效果降低。Cu含量为3.51%、4.52%时,均匀化较彻底;Cu含量为7.51%时,出现共晶偏析,均匀化效果不明显,存在粗大相,降低合金性能。更多还原

【Abstract】 The strength of Al-Li alloy was improved with increasing solubility of Cu in 2A97Al-Li alloy by the near-rapid solidification technology.The mechanical properties of Al-Li alloys with different Cu contents were analyzed by tensile testing.The microstructure of Al-Li alloys with varied Cu content was observed by optical microscopy(OM),scanning electron microscopy(SEM),electron diffraction and energy spectrum(EDS).The results reveal that the tensile strength of the alloy is increased firstly and then decreased with increasing in Cu content.The fracture mode of the alloy is characterized by brittle fracture.And the distribution and proportion of strengthening phase includedθ′,S′andσin alloy can be changed,resulting in the reduction homogenization treatment effect.When the Cu content is 3.51% or4.52%,the homogenization treatment exhibits desirable.However,when the Cu content reaches7.51%,eutectic segregation occurs,and then the effect of homogenization is not obvious.There exists some bulky phases,leading to a decrease of the tensile strength of the alloy.更多还原