【作者】 赵凯；

【导师】 许光明；

【作者基本信息】 东北大学 ， 材料工程（专业学位）， 2021， 硕士

【摘要】 Al-Ti-B中间合金是铝合金最常用的晶粒细化剂,在细化铝合金时,常出现沉淀和大颗粒,导致后期轧制过程中容易产生针孔缺陷,严重影响铝箔质量。有关研究表明,Al-Ce中间合金具有很好的细化效果,因而铝-稀土合金的应用也备受关注,但其细化效果受稀土化合物的形状、分布、尺寸以及细化工艺的影响,并有待系统的研究。本文以工业纯铝和混合稀土 RE(Ce和La)为原料,使用混熔法,通过铸造和铸轧方式,分别制备出Al-8RE、Al-10RE和Al-15RE中间合金,并采用冷轧法制备出冷轧态Al-10RE和Al-15RE中间合金,分析了 Al-RE中间合金的微观组织形貌,探究了 Al-RE中间合金对3102合金组织和性能的影响,初步分析了 Al-RE中间合金的细化机理,并与Al-Ti-B细化剂的细化效果进行对比。论文得出以下结论:(1)Al-RE 中间合金由α-Al、Al11RE3(Al11Ce3和 Al11La3)、Ce 和 La 组成,不同稀土含量的Al-RE中间合金微观组织形貌不同,Al-8RE、Al-10RE和Al-15RE中间合金的组织分别为亚共晶组织,伪共晶组织和过共晶组织,随稀土含量的增加,Al-RE中间合金中Al11RE3相的数量增多,尺寸增大。(2)在铸态、铸轧态和冷轧态Al-RE中间合金中,铸轧态Al-RE中间合金的Al11RE3相尺寸较小,冷轧态Al-RE中间合金Al11RE3相尺寸最小,单位体积内Al11RE3相的数量最多。(3)Al-RE中间合金对3102合金具有显著的细化效果;在Al-8RE中间合金中Al11RE3相尺寸较小,而Al-15RE中间合金中Al11RE3相尺寸较大,导致Al-8RE和Al-15RE中间合金中,异质形核质点数相对较少,对3102合金的细化效果不如Al-10RE中间合金好;对比铸态、铸轧态、冷轧态Al-10RE中间合金对3102合金的细化效果,冷轧态Al-10RE中间合金的细化效果最好,对合金力学性能的提高也最大,其次是铸轧态Al-10RE中间合金。(4)Al-RE中间合金细化3102合金的最佳添加量为1%,最佳保温时间不同,铸态、铸轧态Al-RE中间合金的最佳保温时间为15min,冷轧态Al-RE中间合金的最佳保温时间为10min,Al-RE中间合金具有较好的衰退性能,当保温时间为120min时,对合金仍然有很好的细化效果。(5)Al-Ti-B中间合金对3102合金具有很好的细化效果,最佳添加量为0.3%,最佳保温时间为5min;对比冷轧态Al-RE中间合金与Al-Ti-B中间合金,冷轧态Al-RE中间合金对3102合金的细化效果稍好,对合金力学性能的提高稍大,但二者相差不大。更多还原

【Abstract】 Al-Ti-B master alloy is the most commonly used grain refiner for aluminum alloys.When refining aluminum alloys,precipitation and large particles often appear,which may cause pinhole defects in the later rolling process and seriously affect the quality of aluminum foil.Relevant studies have shown that Al-Ce master alloy has a good refinement effect,so the application of aluminum-rare earth alloys has also attracted much attention,but its refinement effect is affected by the shape,distribution,size and refinement process of the rare earth compound.So it needs to be systematically studied.In this paper,industrial pure aluminum and mixed rare earths RE(Ce and La)are used as raw materials,and Al-8RE,Al-10RE,Al-15RE master alloys are prepared by casting and rolling,respectively,the mixed melting method,and the cold rolling method is adopted to prepare cold-rolled Al-10RE and Al-15RE master alloys,analyze the microstructure and morphology of Al-RE master alloy,explore the influence of Al-RE master alloy on the structure and properties of 3102 alloy,and analyze preliminarily the refinement mechanism of Al-RE master alloy,and compared with the refinement effect of the Al-Ti-B refiner.The paper draws the following conclusions:(1)Al-RE master alloy is composed of α-Al,Al11RE3(Al11Ce3 and Al11La3),Ce and La.The microstructure and morphology of Al-RE master alloys with different rare earth contents are different.The structure of Al-8RE,Al-1ORE,Al-15RE master alloy is hypoeutectic,pseudo-eutectic and hypereutectic,respectively.With the increase of rare earth content,the amount of Al11RE3 in Al-RE master alloy increases and the size increases.(2)In the as-cast,cast-rolled and cold-rolled Al-RE master alloys,the Al11RE3 phase size of the as-cast Al-RE master alloy is smaller,and the cold-rolled Al-RE master alloy Al11RE3 has the smallest size,The number of Al11RE3 phases per unit volume is the largest.(3)Al-RE master alloy has a significant refining effect on 3102 alloy;in Al-8RE master alloy,the size of Al11RE3 phase is small,and Al11RE3 phase will quickly solid dissolve intoα-Al,while Al-15RE master alloy The relatively large size of the Al11RE3 phase results in a relatively small number of heterogeneous nucleation points in the Al-8RE and Al-15RE master alloys,and the refining effect of the 3102 alloy is not as good as that of the Al-10RE master alloy;compare as-cast and cast-rolled The refining effect of the cold-rolled Al-10RE master alloy on the 3102 alloy is the best,the cold-rolled Al-10RE master alloy has the best refining effect and the greatest improvement in the mechanical properties of the alloy,followed by the cast-rolled Al-10RE Master alloy.(4)The optimal addition amount of Al-RE master alloy refined 3102 alloy is 1%,and the optimal holding time is different.The optimal holding time of as-cast and as-rolled Al-RE master alloy is 15min,and that of cold-rolled Al-The optimal holding time of RE master alloy is 10min.Al-RE master alloy has better decay performance.When the holding time is 120min,it still has a good refinement effect on the alloy.(5)Al-Ti-B master alloy has a good refinement effect on 3102 alloy,the optimal addition amount is 0.3%,and the optimal holding time is 5min;compare the cold-rolled Al-RE master alloy with Al-Ti-B master alloy,the cold-rolled Al-RE master alloy has a slightly better refinement effect on the 3102 alloy,and a slightly greater improvement in the mechanical properties of the alloy,but the difference is not much.更多还原