) 上海交通大学 材料科学与工程学院，上海 200240
收稿日期:2019-12-31出版日期:2021-03-01发布日期:2021-04-02通讯作者:沈耀E-mail:yaoshen@sjtu.edu.cn作者简介:唐靖钊(1993-)，男，四川省成都市人，硕士生，主要从事铝合金力学性能与微观结构研究.基金资助:国家重点研发计划(2017YFB0702201)Effect of Silicon State on Microstructure and Properties of Al-1%Si Alloy During Severe Plastic Deformation
TANG Jingzhao, YAN Jiawei, SHEN Yao() School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Received:2019-12-31Online:2021-03-01Published:2021-04-02Contact:SHEN Yao E-mail:yaoshen@sjtu.edu.cn摘要/Abstract
摘要： 合金元素能够以固溶态或纳米颗粒析出形态影响铝合金变形过程中微观组织演化，但哪种形态对铝合金微观组织影响更显著仍有争议．以Al-1%Si合金为研究对象，通过在变形前改变硅原子析出态与固溶态的比例，利用多道次累积叠轧焊方法实现大变形，对比研究了在微观组织和力学性能达到饱和状态过程中纳米析出硅颗粒、晶粒尺寸和位错密度的演化，以比较固溶原子与析出颗粒对铝合金变形过程中组织及性能的影响．结果表明，初始样品中固溶原子越多，析出颗粒越少，变形后饱和位错密度更高，晶粒尺寸更小，对应屈服强度更高．Al-1%Si合金中弥散分布的固溶硅原子比同质量的纳米析出硅颗粒阻碍位错动态回复的总效果更好，与位错理论分析相符．材料内位错回复能力也会影响饱和晶粒尺寸，位错回复能力越强，饱和晶粒尺寸更大.
关键词: Al-1%Si合金, 累积叠轧焊, Si元素形态, 微观组织, 屈服强度
Abstract: Alloy elements can influence the microstructure evolution of aluminum alloys in the state of solid solute atoms or nano-precipitated silicon particles, but it is still a controversial subject which form has a more significant effect on the microstructure of aluminum alloys. Therefore, taking the Al-1%Si alloy as the research object, the ratio of precipitation state and the solid solution state of the silicon atoms was changed before deformation and a multi-pass accumulative roll-bonding method was used to achieve large deformation. In order to compare the influence of solid solute atoms and nano-precipitated silicon particles on the structure and properties of aluminum alloy during deformation, a comparative study was conducted on the evolution of nano-precipitated silicon particles, grain size, and dislocation density in the process of reaching the saturation state of the microstructure and mechanical properties. The results show that the initial samples with less nano-precipitated silicon particles and more solute silicon atoms have a higher saturated dislocation density and a smaller saturated grain size after deformation, corresponding to a higher saturated yield strength. Solid solute silicon atoms dispersed in the Al-1%Si alloy have a better overall effect than nano-precipitated silicon particles of the same volume in preventing the dynamic recovery of dislocations, which is consistent with the theoretical analysis of dislocations. The dislocation recovery ability in the material affects its saturated grain size. The stronger the dislocation recovery capacity, the larger the saturated grain size.
Key words: Al-1%Si alloy, accumulative roll-bonding, alloy element form, microstructure, yield strength
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