【摘要】 利用金相组织观察、扫描电镜分析、X射线衍射分析和拉伸性能检测等方法,研究了不同CeO2含量对2024铝合金显微组织及力学性能的影响。结果表明,CeO2能够细化2024铝合金的铸态组织和退火态组织。CeO2与金属Al反应生成的Ce,与基体中的Al和Cu形成新相Al3Ce、CeCu2。添加CeO2能够提高2024铝合金的抗拉强度和屈服强度,而且添加0.25%(质量分数,下同)时能够获得最佳性能,铸态下的抗拉强度和屈服强度分别提高了55%和50%,退火态下的抗拉强度和屈服强度分别提高了30%和17%。但是CeO2的加入量过高,反而使合金的性能降低。当未添加CeO2时,2024铝合金断口表面呈准解理和韧窝状态,表现为脆性与韧性结合的混合断裂特征,而添加一定量的CeO时,合金呈现出塑性断裂特征。更多还原

【Abstract】 The influences of CeO2 on the microstructure and tensile properties of 2024 aluminium alloy were investigated by means of optical microscopy,scanning electron microscopy,x-ray diffraction and tensile test.The results are as follows: CeO2can refine the grains of casting and annealing 2024 aluminium alloy.Cerium(Ⅳ) oxide can be deoxidized into cerium by aluminium,and new phases Al3Ce and CeCu2 are formed for cerium interacts with aluminium and copper.The tensile strength and yield strengthof 2024 alloy can be improved with addition of CeO2,the optimum addition of CeO2 is 0.25% with the best mechanical properties,and the tensile strength and yield strength in the casting state are improved by 55% and 50%,respectively and that in the annealing state are improved by 30% and 17%,respectively.However,more CeO2 addition makes the properties worse.The fracture mechanism of 2024 aluminium alloy without CeO2 is quasi-cleavage and dimples,the main fractographic appearances are brittle and toughness,while the fracture mode of alloy is ductile fracture with some addition of CeO2.更多还原