Study Of Cold Rolling And Annealing On The Effect Of Interface Layer And Properties Of Cu-Al Composite Plate

Copper-Aluminum composite plate is a double metal composite materials, combines the advantages of low contact resistance、high thermal conductivity of Cu and low density、 cheap price of Al. Now, copper and aluminum composite plate can be seen in the field of high-tech military, aerospace and heat dissipation substrate, electrical appliances, construction and other ordinary civil field.The Copper-Aluminum composite plate studied in this paper was prepared by continuous casting and rolling process. Peel testing machine, tensile testing machine, electrical conductivity meter etc were used to test mechanical properties and electrical conductivity of Copper-Aluminum composite, SEM, EDS, XRD, TEM, and other instruments were used to analyze the interface layer structure and component. The research was mainly focused on the changing rule of interface layer morphology, mechanical properties, electrical conductivity of composite plate with reduction rates and changing rules of the interface layer microstructure, mechanical properties of cold rolled composite plate with different annealing conditions, The results are as follows:1. Using the casting rolling composite method can prepare Cu-Al composite plate with good combined effect and good conductive properties, the interface layer is composed of eutectic structure α-Al+Cu Al2 and Cu Al2, the peal strength is higher than the other composite plate prepared by other process, it’s tensile strength and elongation rate are between Al and Cu, because of the existence of skin effect, the temperature curve of conductive is nearly the same with copper plate..2. Cold rolling process makes the interface layer of composite rupture and crush, and affected properties of composite plate; When the cold-rolling reduction rate from 29% gradually increase to 57%, the fragmentation degree of the interfacial layer gradually increases, the peel strength is reduced rapidly first then slowly increased, the tensile strength of composite plate is increased gradually, the elongation is decreased gradually, at the same time, conductivity is decreased gradually too.3. The microstructure of the interfacial layer and mechanical properties of the composite plate change significantly with different annealing temperature. Annealing treatment with temperature 300℃-400℃recovers the recovers broken interface layer, in which there are three kinds of compounds-Cu Al2, Cu9Al4 and Cu Al. The thickness of each phases grows with the increase of temperature or annealing time, the hardness of matrix is reduced rapidly first then remains stable, the conductive property slowly rises, the peel strength increases first, and reaches a maximum value at 300℃×3h, when the annealing temperature continues to rise, or annealing time continues to increase, the peel strength began to decrease.