Study On The Interface Bonding Strength And Damping Capacity Of NiTi/Al Multilayer Composites By Ultrasonic Additive Manufacturing Method

NiTi-Al metal matrix composites(NiTi-Al MMCs)with embedding Ni Ti shape memory alloys(SMAs)that have sensing and actuating properties into Aluminum foils,which has important significances and applications in the structure life monitoring,self-actuating,adapting,and vibration control fields.NiTi-Al MMCs fabricated by Ultrasonic Additive Manufacturing method(UAM)has attracted much more attention from numerous researchers.The mechanism of fabrication,the temperature history in the fabrication process and the bonding qualities of NiTi-Al MMCs in UAM are key points for UAM to fabricate NiTi MMCs.Firstly,the two dimensional FEM model of the NiTi-Al MMCS fabricated by UAM process from a thermal-mechanical coupling view has been established by ABAQUS.The plastic deformation and temperature of the welding area has been studied to reveal the bonding mechanism in UAM.Then,the influences of the process parameters such as normal pressure,vibration amplitude and welding speed on the plastic deformation and temperature have been researched,and the influence of the welding process parameters on the bonding strength of the NiTi/Al interface also has been researched with orthogonal experiment method,and research results show that the bonding strength of the NiTi-Al interface decrease with normal pressure,vibration amplitude and welding speed.Besides,the bonding strength varies within the range of 10-30 Mpa in the selected process parameters combination.The effects of temperature,NiTi volume fraction and location on the damping capacity of NiTi-Al MMCs beam fabricated by UAM process have been investigated with modal strain energy method.The research results show that the damping capacity of NiTi-Al MMCs could achieve a maximum value when the NiTi is located in the large deformation area,and NiTi is in the martensitic phase in small deformation structures,or with high elastic modulus.