Study On Die Casting And Formation Of Multi-Metal Fiber Aluminum Alloy Aviation Fasteners

With the advancement of science and technology,no matter in the fields of aviation,aerospace,automotive,electronics,etc.Higher requirements have been placed on lightweight and high-strength materials.At present,pure aluminum alloy rivets are soft in texture and not high in strength and hardness.It takes a lot of time in later use,maintenance,and replacement.Therefore,it is of great practical significance to prepare a lightweight high strength aluminum alloy rivet.This paper mainly uses a new type of high-pressure fast-cooling vacuum suction casting process to prepare a metal fiber reinforced ZL105 A aluminum matrix composite rivet.First,a new high-pressure fast-cooling vacuum suction casting system is designed,and the optimal process parameters of the fast-cooling system are determined through simulation analysis.Based on this,a set of composite rivet molds that can be embedded with multi-metal fibers is designed and prepared.Secondly,the finite element Pro CAST software is used to simulate the rivet casting process,explore the forming mechanism and damage mechanism of aviation rivets,and predict the possible locations of defects.Finally,the new system is used to form different metal fiber diameters and metal fiber volume fractions,Metal fiber types,fiber surface copper plating composite rivets under four process parameters,fiber reinforced ZL105 A aluminum-based composite rivets under different process parameters for microstructure observation and performance testing,the main conclusions are The following conclusions:(1)According to the finite element analysis of the forming process of the rivet,the head of the rivet is completely filled first.At the same time,near the metal fibers,reverse filling and uneven heat transfer occur during the casting of the alloy liquid,therefore,the defect location is mainly distributed near the metal fiber and near the casting gate.(2)Copper plating on the surface of the metal fiber can improve the wettability between the fiber and the substrate,and enhance the binding ability between the two.Copper plating on the fiber surface reduces the pores between the fiber and the substrate.The copper plating between the two compensates for the large pores between the two in a high-temperature environment.The eutectic silicon is evenly dispersed in the solid solution with a grain size of 2.3um ? 3.2um.(3)Within a certain range,as the diameter of the metal fiber increases,the mechanical properties of the fiber-reinforced ZL105 A aluminum-based composite material increase first and then decrease.When the diameter of 304 stainless steel fiber is 0.1mm,the maximum tensile strength of the composite material is 341.04 MPa,which is 49.33% higher than that of the matrix;the maximum elongation at section is 54.24 mm,which is 43.3% higher than that of the substrate;The maximum microhardness is 129.1HV,which is 66.56% higher than the matrix.When the Ti Ni metal fiber diameter is 0.1 mm,the tensile strength of the composite material is 367.8 MPa at the maximum,and the section elongation is 54.242 mm at the maximum.(4)The volume fraction of metal fibers increases to some extent,the mechanical properties of the composite material increase first and then decrease.When the volume fraction of 304 stainless steel fiber is 0.17%,the maximum tensile strength of the composite material is 345.05 MPa,which is 66.19% higher than the tensile strength of the ZL105 A aluminum-based alloy matrix at 228.38 MPa.(5)The tensile strength of Ti Ni copper-coated fiber reinforced composite is 7.85% higher than that of 304 stainless steel copper-coated fiber reinforced composite.(6)From the perspective of electrical properties,Within a certain range,as the diameter of the metal fiber increases,the resistivity of the composite material increases first and then decreases.When the diameter of the copper-plated metal fiber is 0.08 mm,the maximum resistivity of the composite material is 25.9??.mm;When the diameter of uncoated copper fiber is 0.2mm,the maximum resistivity of the composite material is 28.2??.mm,and the resistivity of 304 stainless steel fiber reinforced composite material is higher than that of Ti Ni metal fiber reinforced composite material.