Relationship between amounts of low-melting-point eutectics and hot tearing susceptibility of ternary Al−Cu−Mg alloys during solidification  

Al−Cu−Mg合金凝固过程中低熔点共晶体含量与其热裂敏感性之间的关系

作　　者：Jia-qiang HAN Jun-sheng WANG Ming-shan ZHANG Kang-min NIU 韩加强;王俊升;张明山;牛康民(北京科技大学材料科学与工程学院,北京100083;北京理工大学材料学院,北京100081;北京理工大学前沿交叉科学研究院,北京100081)

机构地区：[1]School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China [2]School of Materials Science and Engineering,Beijing Institute of Technology,Beijing 100081,China [3]Advanced Research Institute of Multidisciplinary Science,Beijing Institute of Technology,Beijing 100081,China

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第9期2311-2325,共15页中国有色金属学报（英文版）

摘　　要：A systematical study on the relationship between the amounts of different eutectic phases especially the low-melting-point(LMP)eutectics and the hot tearing susceptibility of ternary Al−Cu−Mg alloys during solidification was performed.By controlling the concentrations of major alloying elements(Cu,Mg),the amounts of LMP eutectics at the final stages of solidification were varied and the corresponding hot tearing susceptibility(HTS)was determined.The results showed that the Al−4.6Cu−0.4Mg(wt.%)alloy,which contained the smallest fraction of LMP eutectics among the investigated alloys,was observed to be the most susceptible to hot tearing.With the amount of total residual liquid being approximately the same in the alloys,the hot tearing resistance is considered to be closely related to the amounts of LMP eutectics.Specifically,the higher the amount of LMP eutectics was,the lower the HTS of the alloy was.Further,the potential mechanism of low HTS for alloys with high amounts of LMP eutectics among ternary Al−Cu−Mg alloys was discussed in terms of feeding ability and permeability as well as total viscosity evolution during solidification.对三元Al−Cu−Mg合金凝固过程中共晶尤其是低熔点共晶含量与热裂敏感性之间的关系进行系统研究。通过控制Al−Cu−Mg合金中主合金元素Cu、Mg的含量,使合金凝固末期的低熔点共晶体含量不同并对相应的热裂敏感性进行评价。结果表明:凝固末期具有最少量低熔点共晶体的Al−4.6Cu−0.4Mg(质量分数,%)对热裂最为敏感。在残余液体的总量基本相等的条件下,不同合金成分抗热裂性能与低熔点共晶含量密切相关,合金热裂抗性与低熔点共晶体含量密切相关,即:低熔点共晶含量越高,合金的热裂抗性越好。最后,从凝固过程中的补缩、渗透率以及整体黏度方面讨论低熔点共晶显示出良好热裂抗性的潜在机理。

关 键 词：Al−Cu−Mg alloy hot tearing SOLIDIFICATION eutectic reaction low-melting-point(LMP)eutectics thermodynamics 

分 类 号：TG146.21[一般工业技术—材料科学与工程]