Effect Of Solution-aging And Multiaxial Compression On The Microstructure And Performance Of Cu-Cr Alloys

The copper alloys with high strength and conductivity are a kind of functional materials which have excellent comprehensive physical properties and mechanical properties.They are widely used in electrical equipment,electric power industry,welding,heat exchangers,etc.How to make the materials with high strength and conductivity simultaneously is a research hotspot.To meet the above requirements,it was a key problem in the design of copper alloys how to effectively coordinate the contradictions between hardness and electric conductivity.This paper mainly has studied four kinds of Cu-Cr-(Si)alloys.The microstructure and precipitation were studied using OM,SEM and TEM,respectively.The hardness and electric conductivity of Cu-Cr alloys prepared with different process were measured.The casting alloys with vacuum induction melting were treated with two kinds of solution processes,one is direct solution and another is solid solution after cold deformation process,whose microstructure and performance were analyzed.The microstructure and performance of alloys deformed with different passes,aging treatment were studied in this paper,and the effect of aging treatment and cold deformation on the properties of alloys were analyzed.The process can be obtained with which can prepare the alloys with simultaneously high strength and high electrical conductivity.The following results were concluded:After solid solution,the hardness of Cu-Cr alloys has increased gradually with the cold deformation,and the conductivity decreased when the deformation reaches a certain amount.The alloys with different composition have different defect forms and defect density,so the density and size of precipitations are different after aging,which affected the hardness and electric conductivity of alloys aging after the cold deformation.The Cu-Cr alloys with high strength and high conductivity can be achieved when the composition of alloys,cold deformation and aging were reasonably chosen.The addition of Si can effectively refine the dendrites of the casting Cu-Cr alloys and eliminate segregation in in solid solution.At the same time,cold deformation before solid solution treatment can also increase the amount of solid solution and eliminate dendritic segregation.After aged and solid solution treated,the second phase precipitated,and the solubility has been reduced,so the hardness and the conductivity of alloys increased with the aging time.