冷却速度对多元铝硅铸造合金组织与性能的影响  

Microstructure and Properties of Multi-Al-Si Casting Alloy with Cooling Rate

作　　者：高续森 郭永春[1] 马志军[1] 王建利[1] 杨忠[1] 李建平[1] Gao Xusen;Guo Yongchun;Ma Zhijun;Wang Jianli;Yang Zhong;Li Jianping(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,陕西西安710021

出　　处：《稀有金属》2020年第4期394-400,共7页Chinese Journal of Rare Metals

基　　金：陕西省创新人才推进计划-科研创新团队项目(2017KCT-05);陕西省重点研发计划-工业领域项目(2018GY-111)资助。

摘　　要：近共晶多元Al-Si合金在汽车、航空、军事领域有广阔的应用前景,通过改变合金冷却速度可以有效改善合金的显微组织。本文通过快速凝固甩带和水冷铜模铸造技术获得Al-11.5Si-4Cu-2.7Ni-Mg-0.45Fe合金,采用金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)等分析测试手段,研究了两种冷却速度对合金微观组织和显微硬度的影响。结果表明,甩带样品的硬度相对水冷铜模样品提高32.22%。此外,水冷铜模铸造使合金显微组织中初生硅尺寸相对常规金属型铸造明显减小;快速凝固甩带样品元素分布较水冷铜模样品更加均匀,甩带样品的微观组织由等轴状α-Al枝晶及少量非晶相组成,不存在明显的凝固析出AlCuNi相,尤其是没有明显Si相的析出。而且,快速凝固甩带试样中Fe元素含量在不同的位置差距比较大,而Mg,Ni,Cu元素的含量差距不大,这与不同金属元素的晶格结构有关。快速凝固甩带的铝相各峰的极值位置相对于水冷铜模向左偏移,即衍射发生小角度偏移,这与合金元素的过固溶有关。Near-eutectic Al-Si multi-component alloy has broad application prospects in automotive,aerospace and militaiy fields,and the microstructure of the alloy could be effectively improved by changing the cooling rate of the alloy.In this paper,Al-11.5 Si-4 Cu-2.7 Ni-Mg-0.45 Fe alloy was obtained by rapid solidification and water-cooled copper casting technique,and analyzed by metallographic microscope(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM) and X-ray diffraction(XRD).The effect of two cooling rates on the microstructure and microhar-dness of the alloy were studied.The results showed that the hardness of the rapid solidification sample was increased by 32.22% compared to that of the water-cooled copper casting sample.In addition,the water-cooled copper casting significantly reduced the size of the primary silicon in the microstructure of the alloy compared with the conventional metal casting.The element distribution of the rapidly solidified annealed sample was more uniform than that of the watercooled copper mold,the microstructure of the rapid solidification sample consisted of equiaxed a-Al dendrites and a small amount of amorphous phase,and there was no obvious solidification and precipitation of AlCuNi phase,especially no precipitation of significant Si phase.Moreover,the content of Fe in the samples of rapid solidification was larger at different positions,while the content of Mg,Ni and Cu was not much different,which was related to the lattice structure of different metal elements.The extreme positions of the peaks of the aluminum phase of the rapidly solidified lanthanum were shifted to the left relative to the water-cooled copper mold,that was,the diffraction had a small angular shift,which was related to the over solid solution of the alloying elements.

关 键 词：快速凝固甩带 水冷铜模铸造 多元铝硅合金 显微组织 显微硬度 

分 类 号：TG27[金属学及工艺—铸造]