Microstructure And Mechanical Properties Of White Copper/steel Clad Strips Prepared By Continuous Solid/liquid Bonding Method

Metal-based layered composite materials are widely used in certain harsh manufacturing environments because they combine the physical properties of two or more alloys.A continuous solid/liquid bonding method was successfully developed to fabricate clad strips with a good metallurgical bonding in the present study.As the typical example,the Cu-10Ni-1Fe(nickel bronze)clad steel composite strips with a size of 650 mm × 100 mm × 8 mm were prepared.In addition,the microstructure was observed by optical microscope(OM),scanning electron microscope(SEM)and electron probe microanalysis(EPMA),which aim to analyze the solidification structure of the iron white copper/steel composite plate and the diffusion behavior of the two materials.The interface was analyzed by means of Vickers hardness,shear tensile strength tests and bending tests.The effects of plastic deformation on the composite interface and diffusion distance were analyzed by cold rolling and hot rolling(30%,50% and 70% respectively).The results show that the microstructure of the as-cast iron white copper/steel composite plate is dendritic ?-Cu and the steel side is ferrite and pearlite.The diffusion layer is mostly present on the side of the iron white copper,and the diffusion distance is about 1.90-2.18?m,which is close to the 1.51?m calculated by the formula.The interface diffusion distance of the coldrolled composite plate from 30% to 70% deformation is 1.57-1.03?m,and the diffusion distance of the hot rolled composite plate is 1.90-0.99?m.It can be seen from the clad ratio that the diffusion distance is reduced because the iron white copper side is subjected to more plastic deformation.However,higher temperature during the hot rolling process promotes the diffusion,so the hot rolled samples diffusion distance is greater than that of the cold rolled samples.However,when the deformation amount exceeds 50%,neither cold rolling nor hot rolling will promote the thickness of the diffusion layer.From the interface shear tensile strength tests,it was found that all the tensile shear specimens were broken at the iron white copper,indicating that the tensile shear strength of the interface was higher than that of the iron white copper.The micro-hardness of the interface indicates that the micro-hardness of the interface region is always higher than that of the iron white copper side and lower than that of the steel side.The benching strength of the as-cast specimen in the three-point bending tests is 851 MPa.When the deformation amount of the cold-rolled samples reached 70%,the benching strength increased to 1105 MPa,and the increase is 30%.The higher benching strength of the as-cast and cold-rolled composite plate indicates that the composite plate has good bending resistance.This study demonstrates that metallurgical bonding between iron white copper and SAE1010 steel can be achieved by a continuous solid/liquid bonding method.The main combination of bimetallic composite plates is the diffusion bonding of elements.