Study On Process And Properties Of Fe-based Amorphous/Al Micro-Laminated Composites

Amorphous alloys,as a kind of metal material with peculiar structure and excellent properties,have attracted great attention in scientific research and industrial application.However,due to the limitations of critical size and preparation technology,amorphous alloys are still difficult to be popularized and applied as large structural materials.At present,the industrialization of amorphous alloys is mainly based on iron-based amorphous ribbons as soft magnetic functional materials,but the application of excellent mechanical properties of ironbased amorphous alloys is neglected.In fact,the strength of iron-based bulk amorphous alloys can exceed 4000 MPa,and the strength of iron-based amorphous soft magnetic alloys can also exceed 3000 MPa in industry.It has the advantages of high hardness and high toughness,and the width of its ultra-thin ribbon(thickness ~ 20um)can reach more than 200 mm.At the same time,the application research shows that the amorphous alloy strip has pure material,uniform chemical composition,amorphous single-phase structure,good diffusion activity and adhesion activity,which make it an ideal carrier for laminated composite materials.Drawing lessons from the bionic design concept of laminated composite materials,using iron-based amorphous ribbons as the strength layer,the diffusion reaction process was designed according to the characteristics of iron-based amorphous structure.By adding soft metal foil,the multi-layer soft metal foil-intermetallic compound-iron-based amorphous ribbons were constructed into high-strength,tough and large-size components,which could make the structure of multi-level and different mechanical properties overlap and promote cracking.Several toughening mechanisms,such as grain passivation,deflection,bending and bridging,have enhanced the composite effect.Therefore,the design and development of new Fe-based amorphous laminated composites will provide new basic application materials for aviation,aerospace and weapon protection.It is also of great academic value to study the mechanism of interfacial reaction and complete the evaluation of the comprehensive performance system of this new material for the regulation and control of multi-layer and multi-phase structure.In addition,because of the good flexibility of iron-based amorphous strips,the one-time processing and forming of complex components can also be realized in the process of lamination heating and pressing with soft metal foil,which is expected to open up a new application direction for amorphous alloys as structural materials and has important engineering significance.In this paper,the microstructure of the material was characterized by metallographic microscope,differential scanning calorimetry,X-ray diffraction,scanning electron microscopy and electron probe.The mechanical properties of the material were analyzed by electronic universal material testing machine,pendulum impact testing machine and Vickers microhardness tester.The effects of hot pressing temperature and time on Fe-based amorphous/Al micro-laminates were studied.The effects of the thickness ratio on the mechanical properties of the composites were investigated by designing the composites with different thickness ratios under the established optimum technological parameters.The main conclusions are as follows:(1)Fe-based amorphous/Al micro-laminated composites with good interfacial bonding were prepared by hot-pressing diffusion composite process.Fe-based amorphous and Al diffused at the interface,forming a diffusion layer dominated by FeAl3 intermetallic compound,forming a multiphase composite structure of Fe-based amorphous strip-intermetallic compound-pure aluminum.(2)The effects of hot pressing temperature and time on Fe-based amorphous/Al microlaminated composites were studied.The results showed that the composite mechanical properties of the samples were better after hot pressing for 5 h at 530(?)C.The bending strength was 227 MPa and the impact absorption energy was 50 J.(3)The effects of different thickness ratios on the properties of Fe-based amorphous/aluminium micro-laminated composites were studied under the optimum process conditions.The results show that with the increase of thickness ratio,the flexural strength increases and the impact performance decreases.When the thickness ratio is 1/25,the impact absorbing power is higher,50 J;when the thickness ratio is 1/5,the flexural strength is higher,340 MPa.(4)The analysis shows that the crack growth of Fe-based amorphous/Al micro-laminated composites is energy dissipation structure,passivation occurs when the crack propagation meets the amorphous layer,and then deflection occurs,resulting in the extension of the propagation path,and bridging occurs in the process,which absorbs a large amount of energy in the deformation process and delays the crack propagation.