Study On Process And Mechanical Properties Of The Preparation Of Aluminum Honeycomb Panels By Self-brazing At Middle Temperature

Aluminum honeycomb panels are widely used in aerospace,rail transportation,architectural decoration and other fields for its light weight,high strength,crush resistance and damping,etc."Lightweight,high-performance,energy-saving and environmentally friendly" is the inevitable trend of the development of new materials.However,the existing honeycomb panels bonded by organic gel are difficult to meet the higher requirements in their application.Self-brazing can achieve the metallurgical bonding of the joints at middle temperature.There is no doubt that it's a new method for producing aluminum honeycomb panels.In this paper,the microstructure and performance of the self-brazing joints were analyzed.Brazing parameters and factors affecting the aluminum honeycomb panels forming were studied,the preparation process was determined.Mechanical properties of the aluminum honeycomb panels prepared by self-brazing were tested.The main research work and results were as follows:?1?ZnCl₂ and SnCl₂ and other activators were added to the CsF-AlF₃ eutectic flux matrix,the self-brazing flux was prepared.The self-brazing flux was used for connecting aluminum alloy sheet with T-joints.The T-joints were bonded soundly and there were no slag and porosity etc defects.?2?Aluminum honeycomb panels were prepared by self-brazing.The brazing parameters were optimized to prepare aluminum honeycomb panels.When the brazing temperature is 570 ?,and brazing time is 30 min,the aluminum honeycomb panels can be prepared.When 1060 foil is chosen to prepare the aluminum honeycomb core,in order to prevent the softening deformation,the aluminum foil?thickness above 0.15mm?should be used,and composite brazing sheet should be chosen as the face panel for the assembly accuracy problem;When composite brazing foil is chosen to prepare the aluminum honeycomb core,3003 aluminum alloy can be chosen as face panel.?3?Microstructure of aluminum honeycomb panel joints was analyzed,in which,aluminum honeycomb panel of 1060 foil: most of the Sn metal distributed along the grain boundaries;and aluminum honeycomb panel of composite brazing foil: Si was polygonal shape or lath-shaped,white metal Sn scattered around the gray rod-like Mn-Fe phase;the component of Sn at brazing seam neither diffuse nor form compound phase after 200 ? high temperature aging,the brazing seam microstructure and component don't change,which is the main reason of good high temperature aging performance of self-brazing aluminum honeycomb panel.?4?The tensile-shear strength of the brazing joints of 1060 aluminum honeycomb panels can reach 90-110 MPa,fracture occurred at the base metal,and the joint strength didn't decrease significantly after corroded by 3%NaCl solution;compression strength of the 1060 aluminum foil?0.15mm?honeycomb panels was 1.75 MPa,and compression strength of the composite foil?0.2mm?honeycomb panels was 3.79MPa;aluminum honeycomb structure having face panel or not didn't influence its carrying capacity,there was no fracture between the core wall after testing;the shear strength of the self-brazed 1060 aluminum honeycomb core measured by three-point bending test was 1.16 MPa,and the stress of face panel was 48.51 MPa.