Microstructure And Properties Of Cu-Fe-Si Alloy For Electromagnetic Shielding

With the increasing use of wireless communication and electronic equipment,people have put forward higher requirements for electromagnetic shielding materials.As a material with both excellent electrical and magnetic properties,Cu-Fe alloy is expected to be mass-produced and widely used in the field of electromagnetic shielding.In this paper,Si elements with different contents were added as the third component in the Cu-Fe alloy,and the deformation heat treatment process of the alloy was optimized.The electrical,magnetic and mechanical properties of the Cu-Fe-Si alloy were systematically studied.The microstructure,aging precipitation phenomenon and strengthening mechanism of the alloy were deeply analyzed.The main conclusions of the study are as follows:（1）In this paper,Cu-10Fe-x Si（x=0,0.4 wt.%,0.8 wt.%,1.6 wt.%）alloys with different Si contents were designed and prepared by vacuum induction melting.The phase composition of the alloy is Cu matrix and different forms of Fe phase.In alloys containing Si,Si preferentially combines with Fe to form Fe₃Si phase.After the as-cast alloy has undergone homogenization,hot rolling and cold rolling successively,the Fe phase and Fe₃Si phase in the alloy are deformed and broken to varying degrees.With the increase of Si content,the hardness of the alloy after cold rolling increases,the electrical conductivity and thermal conductivity first increase and then decrease,and the saturation magnetization increases.The analysis shows that Cu-10Fe-0.4Si has the best comprehensive properties.（2）During the heat treatment process,the overall trend of the properties of Cu-10Fe and Cu-10Fe-0.4Si alloys changing with time is that the hardness decreases and the electrical conductivity increases.It has higher relative conductivity and Vickers hardness than Cu-10Fe alloy.According to the analysis,it was found that heat treatment at 450℃for32 h was the best heat treatment process.（3）Under the optimal heat treatment process,the relative electrical conductivity of Cu-10Fe alloy and Cu-10Fe-0.4Si alloy are 63.20%IACS and 68.02%IACS,respectively,the Vickers hardness is 100.2 HV,97.8HV,and the yield strength is are:308.30 MPa,466 MPa,and the elongation is 29.6%and 29.5%,respectively.The saturation magnetization of Cu-10Fe-0.4Si alloy is 117%of that of Cu-10Fe alloy,and it also has higher electromagnetic shielding efficiency.The electromagnetic shielding efficiency is higher than 100 d B in the electromagnetic wave frequency range of 14 k Hz to 3 GHz.（4）There are two kinds of second phases with different sizes in both Cu-10Fe alloy and Cu-10Fe-0.4Si alloy.The size of the larger-scale second phase is about 100-500 nm,and the size of the smaller-scale second phase is about 100-500 nm.within 50 nm.The large and small second phases in the Cu-10Fe alloy are body-centered cubic Fe phases,and the orientation relationship with the matrix is:（111）Cu//（110）Fe and[01（?）]Cu//[（?）11]Fe,（111）Cu//（110）Fe and[（?）10]Cu//[001]Fe;both large and small second phases in Cu-10Fe-0.4Si alloy are Fe₃Si with face-centered cubic The phase relationship with the matrix is:（200）Cu//（202）Fe₃Si and[01（?）]Cu//[（?）11]Fe₃Si,（111）Cu//（220）Fe₃Si and[1（?）0]Cu//[（?）11]Fe₃Si.34 Figures,4 Tables,87 References are contained.