Ni/Ti Multilayered Composites After Accumulative Roll Bonding

Metal laminated composite materials can improve many deficiencies of properties of the single metal material,there is a significant mechanical,electrical,magnetic properties.Accumulative roll bonding(ARB) technology has been successfully used in the production of multilayer structure composite materials of which are Large,bulk and dense,its advantages with simple process and low cost has attracted much attention,and it has wide application prospect.The accumulative roll bonding were used to prepare the Ni/Ti/Ni multilayer composite board.The interface,microstructure and properties of Ni/Ti multilayer composites in various state were observed,measured and analyzed by scanning electron microscope,optical microscope,electronic tensile machine and microhardness tester.The main results are as follows: composite material with flat plate,good interface bonding,good mechanical properties when the rolling temperature is to 400? to 500? and rolling reduction is 50%.The composite interface is straight and there is no diffusion layer at the interface;compare to the raw material,the tensile strength and hardness of composite material increased,the elongation decreased, and the change is significant with increasing passes,the tensile strength and elongation of the composite material is as highest as 684 MPa and16%.When the heat treatment temperature is 200?~500?,the time is 0.5h~8h, the microstructure of nickel and titanium are change from fibrous to equiaxed microstructure,the tensile strength and hardness of composite material are downward trend overall.The low temperature rolling process of composite plate experience surface crack and physical bonding phase mainly,with the increase of temperature,the extension of time,the interfacial bonding strength is improved,but there is not intermetallic compounds at the interface also.When the heat treatment temperature is 800?~930?,the time is 3h~10h,Three kinds of the intermetallic compounds which are Ti Ni3?Ti Ni?Ti2Ni have been formed.With the increase of temperature and the extension of time,the species of the intermetallic compounds did not change, just the thickness has changed, it is as thickest as 200.49 um.