Preparation And Toughening Mechanism Of ZrCoCu Alloy With High Strength And High Toughness

With the rapid development of the modern industry and science technology,the properties of materials,such as strength,hardness,plasticity and toughness,are being put forward to higher requirements in many fields.Most intermetallic compounds have attracted more and more attention due to their high strength and toughness,which show great potential applications.However,intermetallic compounds are less ductile at room temperature.Therefore,improving the comprehensive mechanical properties?high strength,high toughness and high plasticity?of intermetallic compounds has become the main research of scholars.In this paper,ZrCo and ZrCu based alloys with B2 structure are bacame the research subject.Taking high purity Zr,Co and Cu as raw materials,Zr-Co-Cu alloys were prepared by using suction casting technology for water-cooled copper mould.The influence of alloy composition on the microstructure of Zr-Co-Cu alloys were investigated X ray diffraction analyzer,optical metallographic microscope,transmission electron microscope.The influence of alloy composition on the comprehensive mechanical properties of the alloys were investigated automatic turret digital display microhardness tester,nano indentation tester,electronic universal testing machine and tungsten filament scanning electron microscope,respectively.The mechanism of toughening and toughening of the alloy by deformation-induced phase change?DIMT?and its accompanying phase change induced plasticity?TRIP?was also discussed.Studies have shown that:The microstructure and mechanical properties of ZrCo based alloys with different Cu contents and ZrCo based alloys with different Co contents were different.The microstructure of Zr₅₀Co_50-xCu_x?0,5,10,15,20,25 at.%?alloys changed from B2 single ZrCo phase to ZrCo phase and ZrCu phase of B2 structure with the increasing of Cu content,resulting in grain refinement,increasing hardness and strength,and decreasing ductility.The ZrCo phase of B33structure and ZrCu phase of B19'structure were found in the alloys after compression at room temperature.This phenomenon indicates that the phase transition effect induced by deformation occurs;It was found that the microhardness of the alloys after room temperature deformation was improved,and the hardness of the alloy was improved by B19'phase and B33 phase and machining hardening.The microstructure of Zr₅₀Cu_50-xCo_x?0,5,10,15,20,25 at.%?alloys changed from ZrCu martensite phase and part of the amorphous phase to ZrCo phase and ZrCu phase of B2 structure with the increasing of Co content.The grain of the alloy changed from strip martensite to dendrite and finally to fine equiaxed grain.Decreasing strength and increasing ductility.The ZrCo phase of B33 structure and ZrCu phase of B19'structure were found in the alloys after compression at room temperature.This phenomenon indicates that the phase transition effect induced by deformation occurs;Moreover,the XRD peaks show diffuse scattering peaks after deformation,which indicates that the deformation promotes the alloy to transform into amorphous alloy;It was found that the microhardness of ZrCu based alloys after room temperature deformation was improved.The amorphous phase,B19'phase,B33 phase and working hardening in the alloy resulted in the improvement of the hardness.