The oxide layer on the surface has always been a key obstacle to achieving the diffusion bonding of Al alloys.It is a challenge for performing diffusion bonding without removing oxide layers.Herein,diffusion bonding o...The oxide layer on the surface has always been a key obstacle to achieving the diffusion bonding of Al alloys.It is a challenge for performing diffusion bonding without removing oxide layers.Herein,diffusion bonding of Al alloy retaining continuous oxide layers was successfully achieved in the air by a low-temperature and low-pressure diffusion bonding mothed using a Zn interlayer.During the bonding processes,conducted at 360℃ and 3 MPa,Zn diffused into Al through cracks of thin oxide layers to form the joint composed Al/(diffusion layer)/(oxide layer)/(Zn)/(oxide layer)/(diffusion layer)/Al.The diffusion layers were composed of Zn-Al eutectoid,and the oxide layer included nanocrystals and amorphous Al_(2)O_(3).The shear strength of joints containing continuous oxide layers was about 30 MPa.Interestingly,the migration behavior toward the joint center of the interfacial oxide layers was observed with consuming of the Zn interlayer.The cracking phenomenon,the“subcutaneous diffusion”and the migration behavior of oxide layers were verified and analyzed by the diffusion bonding of anodized 6063Al-6063Al.Subsequently,the dynamic migration mechanism of oxide layers with elements diffusion and bonding interface strengths were discussed in detail.The ability to join Al alloys in the air at low temperatures and low pressure suggests a highly practical and economic method for diffusion bonding.展开更多
Because of the challenge of compounding lightweight,high-strength Ti/Al alloys due to their considerable disparity in properties,Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer ...Because of the challenge of compounding lightweight,high-strength Ti/Al alloys due to their considerable disparity in properties,Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer composite plate by explosive welding.The microscopic properties of each bonding interface were elucidated through field emission scanning electron microscope and electron backscattered diffraction(EBSD).A methodology combining finite element method-smoothed particle hydrodynamics(FEM-SPH)and molecular dynamics(MD)was proposed for the analysis of the forming and evolution characteristics of explosive welding interfaces at multi-scale.The results demonstrate that the bonding interface morphologies of TC4/Al 6063 and Al 6063/Al 7075 exhibit a flat and wavy configuration,without discernible defects or cracks.The phenomenon of grain refinement is observed in the vicinity of the two bonding interfaces.Furthermore,the degree of plastic deformation of TC4 and Al 7075 is more pronounced than that of Al 6063 in the intermediate layer.The interface morphology characteristics obtained by FEM-SPH simulation exhibit a high degree of similarity to the experimental results.MD simulations reveal that the diffusion of interfacial elements predominantly occurs during the unloading phase,and the simulated thickness of interfacial diffusion aligns well with experimental outcomes.The introduction of intermediate layer in the explosive welding process can effectively produce high-quality titanium/aluminum alloy composite plates.Furthermore,this approach offers a multi-scale simulation strategy for the study of explosive welding bonding interfaces.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.51975152.
文摘The oxide layer on the surface has always been a key obstacle to achieving the diffusion bonding of Al alloys.It is a challenge for performing diffusion bonding without removing oxide layers.Herein,diffusion bonding of Al alloy retaining continuous oxide layers was successfully achieved in the air by a low-temperature and low-pressure diffusion bonding mothed using a Zn interlayer.During the bonding processes,conducted at 360℃ and 3 MPa,Zn diffused into Al through cracks of thin oxide layers to form the joint composed Al/(diffusion layer)/(oxide layer)/(Zn)/(oxide layer)/(diffusion layer)/Al.The diffusion layers were composed of Zn-Al eutectoid,and the oxide layer included nanocrystals and amorphous Al_(2)O_(3).The shear strength of joints containing continuous oxide layers was about 30 MPa.Interestingly,the migration behavior toward the joint center of the interfacial oxide layers was observed with consuming of the Zn interlayer.The cracking phenomenon,the“subcutaneous diffusion”and the migration behavior of oxide layers were verified and analyzed by the diffusion bonding of anodized 6063Al-6063Al.Subsequently,the dynamic migration mechanism of oxide layers with elements diffusion and bonding interface strengths were discussed in detail.The ability to join Al alloys in the air at low temperatures and low pressure suggests a highly practical and economic method for diffusion bonding.
基金Opening Foundation of Key Laboratory of Explosive Energy Utilization and Control,Anhui Province(BP20240104)Graduate Innovation Program of China University of Mining and Technology(2024WLJCRCZL049)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_2701)。
文摘Because of the challenge of compounding lightweight,high-strength Ti/Al alloys due to their considerable disparity in properties,Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer composite plate by explosive welding.The microscopic properties of each bonding interface were elucidated through field emission scanning electron microscope and electron backscattered diffraction(EBSD).A methodology combining finite element method-smoothed particle hydrodynamics(FEM-SPH)and molecular dynamics(MD)was proposed for the analysis of the forming and evolution characteristics of explosive welding interfaces at multi-scale.The results demonstrate that the bonding interface morphologies of TC4/Al 6063 and Al 6063/Al 7075 exhibit a flat and wavy configuration,without discernible defects or cracks.The phenomenon of grain refinement is observed in the vicinity of the two bonding interfaces.Furthermore,the degree of plastic deformation of TC4 and Al 7075 is more pronounced than that of Al 6063 in the intermediate layer.The interface morphology characteristics obtained by FEM-SPH simulation exhibit a high degree of similarity to the experimental results.MD simulations reveal that the diffusion of interfacial elements predominantly occurs during the unloading phase,and the simulated thickness of interfacial diffusion aligns well with experimental outcomes.The introduction of intermediate layer in the explosive welding process can effectively produce high-quality titanium/aluminum alloy composite plates.Furthermore,this approach offers a multi-scale simulation strategy for the study of explosive welding bonding interfaces.
