半固态加工过程对Al-Fe-Cu合金中Cu元素偏聚及性能的影响
发布时间：2018-10-16 10:13
【摘要】：由于半固态成形工艺过程中熔体存在强制对流现象，导致含铜铝合金在凝固过程中出现Cu元素偏聚现象，而合金中含有Fe元素时，也会对这种Cu元素的偏聚现象产生影响。分析这种现象产生的原因及规律，对认识半固态加工铝合金中的Cu元素分布行为，以及对合金制备、热处理工艺的制定和研究开发适合半固态成形的新工艺均具有理论意义和实用价值。 本文研究了半固态制坯、二次加热重熔和触变成形阶段对Al-Fe-4Cu合金中Cu元素偏聚的影响，并研究了热处理工艺与合金性能的关系。获得了半固态制坯和二次加热重熔阶段合金中Cu元素偏聚规律，以及合适的强化热处理工艺。实验中选用了不同的电磁搅拌电流以及不同的二次加热温度等工艺参数，分析了工艺因素与Cu元素偏聚的关系，目的是为半固态加工工艺的制定提供指导；通过正交试验分析了时效处理工艺参数对合金性能的影响，从而实现了热处理工艺的优化。 不加电磁搅拌电流实验结果表明，Cu元素在晶界处发生偏聚，且偏聚十分明显；施加不同电磁搅拌强度实验表明，电磁搅拌有利于改善Cu元素的偏聚现象，，当搅拌电流分别为40A、60A、80A和100A情况下，搅拌电流越大，改善铜元素在制坯阶段的偏聚现象越明显。二次加热重熔实验表明，在分别采用650℃、660℃、670℃和680℃进行二次加热重熔实验时，重熔区内的Cu元素趋于均匀分布，且加热温度越高，重熔区越大，在重熔区内的Cu元素分布月均匀；触变成形后，Cu元素在富Fe相表面出现了偏聚现象；合金热处理正交实验结果表明，当热处理工艺为520℃固溶10h然后进行175℃的4h人工时效时，合金的硬度达到最高值。
[Abstract]:Due to the phenomenon of forced convection in the melt during semisolid forming process, the phenomenon of Cu segregation occurs in the solidification process of Cu-containing aluminum alloy, and when the alloy contains Fe element, it will also have an effect on the segregation of this kind of Cu element. The causes and rules of this phenomenon are analyzed, and the distribution behavior of Cu elements in semi-solid processing aluminum alloy and the preparation of the alloy are analyzed. The formulation of heat treatment process and the research and development of a new process suitable for semi-solid forming are of theoretical significance and practical value. In this paper, the effect of semi-solid billet making, secondary heating remelting and thixoforming on the segregation of Cu elements in Al-Fe-4Cu alloy is studied, and the relationship between heat treatment process and the properties of the alloy is also studied. The segregation rule of Cu elements in semi-solid billets and secondary heating remelting alloys was obtained, and the appropriate strengthening heat treatment process was also obtained. In the experiment, different electromagnetic stirring current and different secondary heating temperature were selected to analyze the relationship between the process factors and the segregation of Cu elements, in order to provide guidance for the formulation of semi-solid processing technology. The influence of aging process parameters on the properties of the alloy was analyzed by orthogonal test, and the heat treatment process was optimized. The results of experiments without electromagnetic stirring current show that the segregation of Cu elements at grain boundaries is very obvious, and the experiment of different electromagnetic stirring intensity shows that electromagnetic stirring can improve the segregation of Cu elements. When the stirring current is 40A, 60A, 80A and 100A respectively, the bigger the stirring current is, the more obvious is the phenomenon of improving the segregation of copper element in the process of billet production. The secondary heating remelting experiments show that the Cu elements in the remelting zone tend to distribute uniformly when the remelting experiments are carried out at 650 鈩
本文编号：2274033
[Abstract]:Due to the phenomenon of forced convection in the melt during semisolid forming process, the phenomenon of Cu segregation occurs in the solidification process of Cu-containing aluminum alloy, and when the alloy contains Fe element, it will also have an effect on the segregation of this kind of Cu element. The causes and rules of this phenomenon are analyzed, and the distribution behavior of Cu elements in semi-solid processing aluminum alloy and the preparation of the alloy are analyzed. The formulation of heat treatment process and the research and development of a new process suitable for semi-solid forming are of theoretical significance and practical value. In this paper, the effect of semi-solid billet making, secondary heating remelting and thixoforming on the segregation of Cu elements in Al-Fe-4Cu alloy is studied, and the relationship between heat treatment process and the properties of the alloy is also studied. The segregation rule of Cu elements in semi-solid billets and secondary heating remelting alloys was obtained, and the appropriate strengthening heat treatment process was also obtained. In the experiment, different electromagnetic stirring current and different secondary heating temperature were selected to analyze the relationship between the process factors and the segregation of Cu elements, in order to provide guidance for the formulation of semi-solid processing technology. The influence of aging process parameters on the properties of the alloy was analyzed by orthogonal test, and the heat treatment process was optimized. The results of experiments without electromagnetic stirring current show that the segregation of Cu elements at grain boundaries is very obvious, and the experiment of different electromagnetic stirring intensity shows that electromagnetic stirring can improve the segregation of Cu elements. When the stirring current is 40A, 60A, 80A and 100A respectively, the bigger the stirring current is, the more obvious is the phenomenon of improving the segregation of copper element in the process of billet production. The secondary heating remelting experiments show that the Cu elements in the remelting zone tend to distribute uniformly when the remelting experiments are carried out at 650 鈩
本文编号：2274033
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