Study On The Solidification Structure And Properties Of Cu-Fe Alloy

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 less than3%. There is no obvious correlation between the quantities and size of Fe phases and cooling rate when Fe content is greater than3%.