富Ce稀土对多元Al-Si活塞合金凝固组织的影响  

Effect of Ce-rich Rare Earth on Solidification Microstructure of Multicomponent Al-Si Piston Alloy

作　　者：刘铁羽 董雄博 段洪波[1] 夏峰[1] 杨伟[1] 王建利[1] 李建平[1] LIU Tieyu;DONG Xiongbo;DUAN Hongbo;XIA Feng;YANG Wei;WANG Jianli;LI Jianping(Engineering Research Centre of Light Alloys and Composites of Shaanxi Province,School of Materials and Chemical Engineering,Xi'an Technological University,Xi'an 710021,China)

机构地区：[1]西安工业大学材料与化工学院陕西省铝镁轻合金复合材料工程研究中心,陕西西安710021

出　　处：《热加工工艺》2024年第9期95-100,共6页Hot Working Technology

基　　金：陕西省重点研发计划项目(2020ZDLGY13-01);西安市智能兵器重点实验室项目(2019220514,SYS020CG 042)。

摘　　要：采用DSC以及光学显微镜与扫描电镜研究了富Ce稀土(0.1wt%,0.3wt%,0.5wt%)对多元近共晶Al-11.5Si-4Cu-2Ni-1Mg-0.5Fe(wt%)活塞合金凝固组织的影响。发现富Ce稀土加入对该合金的共晶硅和多种第二相的凝固温度、形态与体积分数均有明显影响。富Ce稀土的加入,使Al-Si共晶温度降低,T-Al_(9)FeNi相和δ-Al_(3)CuNi相析出温度升高。富Ce稀土加入量0.3wt%时,共晶硅变质效果最佳,T-Al_(9)FeNi相由初始的板条状转变为小块状,体积分数减小到3.22vol%,δ-Al_(3)CuNi相由初始的片状转化为鱼骨状,体积分数增加到6.47vol%。富Ce稀土中La、Ce原子在凝固过程中富集在固液界面前沿,增大了成分过冷,细化共晶组织。当富Ce稀土含量为0.5wt%时,合金中出现长针状富稀土相。The effect of Ce-rich rare earth(0.1wt%,0.3wt%,0.5wt%)on the solidification microstructure of multivariate near-eutectic Al-11.5Si-4Cu-2Ni-1Mg-0.5Fe(wt%)piston alloy was studied by DSC,optical microscopy and scanning electron microscopy.It is found that the addition of Ce-rich rare earth has obvious effects on the solidification temperature,morphology and volume fraction of eutectic silicon and various second phases of the alloy.The addition of Ce-rich rare earth reduces the Al-Si eutectic temperature and increases the precipitation temperature of T-Al_(9)FeNi phase and δ-Al_(3)CuNi phase.When the addition of Ce-rich rare earth is 0.3wt%,the modification effect of eutectic silicon is best,T-Al_(9)FeNi phase changes from the initial lath shape to the small block shape,the volume fraction decreases to 3.22vol%,and the δ-Al_(3)CuNi phase changes from the initial flake shape to fishbone shape,the volume fraction increases to 6.47vol%.La and Ce atoms in the Ce-rich rare earth are enriched at the front of the solid-liquid interface during the solidification process,which increases the compositional supercooling and refines the eutectic structure.When the content of Ce-rich rare earth is 0.5wt%,long needle-like rare earth-rich phase appears in the alloy.

关 键 词：铝-硅活塞合金 变质 共晶硅 富铈稀土 

分 类 号：TG292[金属学及工艺—铸造] TG244