Ce对Al-5Cu合金组织和性能的影响

Effects of Ce on Microstructures and Properties of Al-5Cu Alloy

通过光学显微镜、X射线衍射仪、场发射扫描电镜、能谱仪、同步热分析等手段,研究了Ce含量对Al-5Cu合金显微组织和力学性能的影响。结果表明,加入Ce元素后,除了α-Al和Al_(2)Cu相外还会生成针状Al8CuCe4相。合金固相线温度升高,液相线温度降低,凝固温度区间缩短,α-Al得以有效细化和均匀化。随着Ce含量增加,共晶Al_(8)CeCu_(4)相逐渐增多,Al_(2)Cu相在Al_(8)CeCu_(4)相边缘附着生长,逐渐形成了沿晶界分布的封闭网状结构。经过T5热处理后Al_(2)Cu相以粒状弥散析出,基体Cu含量增大,耐热性强的Al8CuCe4相形态基本不变。合金的抗拉强度、屈服强度和伸长率均先增大后减小。当Ce含量为0.3%时,合金力学性能最优,抗拉强度、屈服强度和伸长率分别为320 MPa、238 MPa和13.6%,较铸态的明显提高。

Effects of Ce on microstructure and mechanical properties of Al-5Cu alloy were investigated by optical microscopy,X-ray diffraction,FSEM,EDS and DSC.The results indicate that the accicular Al8CuCe4 phase can be generated except forα-Al and Al_(2)Cu phases after Ce addition.With the increase of solidus temperature,decrease of liquidus temperature and shortening of solidification temperature interval,α-Al can be refined and homogenized effectively.With the increase of Ce content,the amount of eutectic Al_(8)CeCu_(4)phase is increased,and Al_(2)Cu phase presents attached growth on the edge of Al_(8)CeCu_(4)phase,forming a closed network structure along the grain boundary.After T5 heat treatment,Al_(2)Cu phase is precipitated dispersedly in granular form,the morphology of Al_(8)CuCe_(4)phase with strong heat resistance is stable,and Cu content of the matrix is raised.The tensile strength,yield strength and elongation of the alloy are increased at first and then decreased.When the content of Ce is 0.3%,the mechanical properties presents desirable,where the tensile strength,yield strength and elongation are 320 MPa,238 MPa and 13.6%,respectively,which is obviously improved compared with those of ones in as-cast state.