Al-Mg-Si变形合金的铸态组织特征

As-cast Microstructure Characteristics of a New Wrought Al-Mg-Si Alloy

制备了一种含Er和Zr元素的板材用Al-Mg-Si合金,其化学成分为Al-0.8Mg-1.0Si-0.8Cu-0.2Mn-0.15Zr-0.3Er。通过透射电镜、X射线衍射、扫描电镜、能谱和光学显微镜等分析,研究了合金铸态组织特征,探讨了合金均匀化退火前后析出相的变化。结果表明,添加Er、Zr元素后,铸锭的晶粒多呈等轴晶,第二相主要为Mg2Si、Al1.9CuMg4.1Si3.3、CuAl2、Al4Mn3Si2、初生Al3Er、Al3Zr和β-Si相;均匀化退火后,第二相质点分布均匀,Mg2Si、Al1.9CuMg4.1Si3.3、CuAl2相溶解消失,过饱和固溶Er元素析出,形成与基体共格的Al3Er相粒子,并形成了核壳状Al3(Er,Zr)复合相。

A kind of Al-Mg-Si alloy contained Zr and Er element for sheet was prepared.The alloy composition is Al-0.8Mg-1.0Si-0.8Cu-0.2Mn-0.15Zr-0.3Er.As-cast and homogenized microstructure of the alloy prepared was observed by transmission electron microscope（TEM）,X-ray diffraction（XRD）,scanning electron microscope（SEM）,energy dispersive spectrum（EDS）and optical microscope（OM）.Meanwhile,the types and changes of precipitation phase in as-cast and homogenization state were analyzed.The results indicate that with Er and Zr addition in casting ingot,the equiaxed grain in the alloy prepared can be observed,and the second phases mainly existing in casting alloy include Mg2Si、Al1.9CuMg4.1Si3.3、CuAl2、Al4Mn3Si2、primary Al3Er、Al3Zr andβ-Si.After homogenization treatment,the second phase particles are distributed more uniformly,improving microstructure of the alloy,and Mg2Si、Al1.9CuMg4.1Si3.3and CuAl2 phases are fully dissolved into the alloy during homogenizing treatment.There are coherent Al3 Er particles precipitate from supersaturated Er solution,and the Al3（Er,Zr）composite phase with a core-shell structure is formed.