摘要本文主要研究了旋转磁场对铜合金凝固组织以及硬度的影响。在铜合金的凝固过程中，通过旋转磁场的作用，可以显著的使合金组织的晶粒细化，抑制初生相的生长，并且对消除宏观偏析、减小柱状晶的相对体积也有非常好的效果。选取的工艺参数有磁场强度、磁场搅拌时间。实验结果表明：旋转磁场对铜合金组织晶粒细化效果明显，让粗状的原先的柱状晶变为颗粒细小的柱状晶或者是等轴晶，晶间距离明显减小。随着磁场强度的增大，旋转磁场产生的洛伦磁力更容易打碎树枝状晶，组织明显细化。磁场搅拌时间越长，增大了热扩散率，使晶核增多，分布均匀，从而细化晶粒，推动柱晶—等轴晶转变。较佳的旋转磁场搅拌工艺参数为：铜银合金浇注温度1250℃、磁场强度2。5mT、磁场搅拌时间20S。铜锡合金旋转磁场强度2。8mT，搅拌时间20S。铜镁合金旋转磁场强度2。8mT，磁场搅拌时间13S。纯铜试样旋转磁场强度2。8mT，搅拌时间17S，74625

毕业论文关键词：铜合金；晶粒细化；宏观组织

Study on Grain Refinement of Copper Alloy

Abstract In this research,we have studied rotating magnetic field effects on the macro-organization and performance characteristics of Cu alloy。 through the action of rotating magnetic field can significantly the grain refinement of microstructure, inhibition of primary phase of growth, and to eliminate macro segregation, reducing the relative volume of the column shaped body also has very good effect。 The selection of technological parameters of the magnetic field strength, magnetic field stirring time。 The experimental results show that the microstructure of Cu alloy is columnar crystal and equal axial grain, and so on。 The rotating magnetic field has obvious effect on the microstructure and grain refinement of the copper and silver alloy。 The original dendritic crystal of the solidified structure is changed to the columnar crystal, and the distance between the crystal and the crystal is obviously reduced。 The higher pouring temperature makes the metal liquid flow stronger, avoiding the defects such as cold insulation and slag inclusion in the casting process。 With the increase of the magnetic field intensity, the microstructure was refined, and the columnar crystals and the other axial grains were orderly。 The longer the stirring time of the magnetic field increases the heat diffusion rate, which makes the liquid metal grains increase, and the distribution of the particles is uniform。

Key words: Copper alloy; Grain refinement; Macro organization

目录

1。前言 1

1。1铜合金的特性及分类 1

1。2高铁用铜合金种类及特点 1

1。2。1 铜合金接触线的种类及特点 2

1。2。2 高铁对接触线的性能要求 2

1。2。3铜合金接触线的研究进展 3

1。2。4 铜镁合金相图 3

1。3铜合金晶粒细化研究进展 4

1。4旋转磁场对合金凝固组织的影响 4

1。4。1旋转磁场对金属液凝固组织作用机理 4

1。4。2旋转磁场对金属凝固组织细化晶粒的影响 5

1。5影响铜合金凝固组织的因素 6

1。5。1浇注温度 6

1。5。2磁场强度 6

1。5。3磁场搅拌时间