导　　师： 李宝绵

学科专业： 080503

授予学位： 硕士

作　　者： ;

机构地区： 东北大学

摘　　要： Cu-Fe系合金是制备引线框架、高速铁路接触线和脉冲强磁场线圈的主要材料,但生产中还存在一些的问题：引线框架用低Fe含量的Cu-Fe系合金铸造时极易产生裂纹,高Fe含量的形变原位复合Cu-Fe系合金铸造时Fe质点粗大且分布不均匀。为了解决此问题,提高该系合金产品的综合性能,必须寻求新的调控该系合金凝固组织的手段。本文主要研究了冷却速度和电磁场对Cu-Fe系合金凝固组织和性能的影响规律,通过研究得到如下结论： 1.随Fe含量的增加,铸态晶粒明显细化,但当Fe含量大于3/%时晶粒细化效果降低；施加磁场可细化Fe含量小于3/%的合金的晶粒,且电流强度越大效果越明显,但当Fe含量大于3/%时效果不明显： 2.施加磁场可使初晶y-Fe的尺寸减小、分布均匀并使析出相的数量和尺寸减少,且电流强度越大效果越显著；改变磁场频率效果不明显； 3.Cu-Fe系合金的凝固组织形态主要由Fe含量决定,当Fe含量小于2.4/%时,组织基本由柱状晶组成,而当Fe含量大于2.4/%时,凝固组织基本由等轴晶组成；当Fe含量在2.4/%左右时,合金的组织由冷却速度决定,冷却速度快时组织由等轴晶组成,冷却速度较慢时组织由柱状晶和等轴晶组成； 4.当Fe含量小于3/%时,随冷却速度的增加,合金中Fe相的数量减少、尺寸变化不大；当Fe含量大于3/%时,合金中Fe相的数量和尺寸与冷却速度没有明显的相关性。 Cu-Fe alloy is the most widely used lead frame material, contact line of high-speed railway and magnetic coil at present. The following problems are existed in the practical production of Cu-Fe alloy. The problem of low Fe content alloy is the cracks in the ingot, which greatly decreases the finished product rate. The problem of Deformation-processed Cu-Fe in-situ composite is the macrosegregation in casting alloy. Aiming at solving this problem, researchers are taking more insight into the approach to control microstructure of Cu-Fe alloy. In this thesis, the effect of electromagnetic field and cooling rate on the solidification structure and properties of Cu-Fe alloy are researched. The following conclusions are obtained: 1. The grain size becomes smaller with increase in Fe content, but the grain refining effect decreases when Fe content is greater than3/%. The grain size becomes smaller with the application of electromagnetic field in the solidification of Cu-Fe alloy with low Fe content /(<3/%/). The effect becomes obvious with the increase in current intensity, but decreases when Fe content is greater than3/%. 2. Electromagnetic field can reduce the dimensions of γ-Fe and make them distribution evenly. These effects become more obvious with the increase in current intensity. The change in current frequency has little effect on the dimensions of γ-Fe and their distribution. 3. The structure morphology of Cu-Fe alloy is decided mainly by the Fe content. When Fe content is less than2.4/%, the structure is composed of columnar crystals; when Fe content is greater than2.4/%, the structure is composed of equiaxed grains; when Fe content is around2.4/%, the structure is decided by cooling rate. The structure is composed of equiaxed rains with high cooling rate, and that is composed of equiaxed grains and columnar crystals with low cooling rate. 4. The quantities of Fe phases are reduced significantly with the increase in cooling rate, and the size of Fe phases has no big change when Fe content is

关 键 词： 合金 晶粒细化 冷却速度 电磁场 凝固组织

领　　域： [金属学及工艺] [一般工业技术] [金属学及工艺]