| In this paper,the amorphous composite structural steel with Fe-Mn-Si-Cr-C composition system was designed.Fe-15Mn-5Si-XCr-0.2C metallic glass composites sample with 2 mm diameter were prepared by the suspend melting water cooled Cu mold process.The effects of Cr content and cold-heat cycling treatment on the structure and mechanical properties of the alloy system were systematically studied.The corrosi on resistance and magnetic properties of the amorphous composite structural steel were also analyzed.The results show that,the sample of Fe-15Mn-5Si-XCr-0.2C?X=1,2,4,6,8,10,12,13,14?amorphous steel system is composed of amorphous phase and crystalline phase(ferrite phaseFe-Cr and austenite phase CFe15.1);With the increase of Cr element,the ferrite phase and amorphous phase increasing,and the austenite phase content increases first and then decreases;TRIP effect is significant during room temperature compression,and the content of martensite induced by deformation increases first and then decreases.The more the content of Cr element increases,the better the comprehensive mechanical properties of the samples?X=14,the yield strength is 978 MPa and the compressive plasticity is 35.8%?.The amorphous phase still exists in Fe-15Mn-5Si-XCr-0.2C?X=10,14?alloy sample after cold and hot cycling treatment,and the atomic arrangement is more orderly,the degree of disordered compact heap becomes larger,and the content of crystal phase increases.The comprehensive mechanical properties of the specimens are greatly improved,the yield strength and plasticity increase by about 10%and 12%,among which the comprehensive mechanical properties of the sample with 10 cycles and 423 K annealing holding temperature are better.The number of germination and propagation of shear band increased in surface,and the number of dimples became more dense,the compressive plasticity was more excellent,and the microha rdness was increased.At the same time,the corrosion resistance of the alloy system in artificial seawater solution was studied.The more the content of Cr element,the better the corrosion resistance.When X=14,the Fe-15Mn-5Si-14Cr-0.2C sample showed good self-passivation behavior in artificial seawater.Compared with 304 stainless steel,the alloy has showed high free corrosion potential,low free corrosion current density,high polarization resistance,large resistance arc radius,only one high frequen cy resistance arc and low corrosion kinetic rate,which were-211.85 mV,0.490?A·cm-22 and 8.9×106??cm2.The corrosion kinetics rate is much lower than 304 stainless steel.No pitting corrosion pits and corrosion products were found after electrochemical corrosion,dense Cr2O3 oxide film formed by the reaction between sample and medium distributes evenly,which prevents the anodic dissolution reaction of Fe;The amorphous phase has no crystal phase defects such as grain boundary dislocation,which makes the amorphous phase have excellent corrosion resistance.And the thickness of passivation film increases with the increase of Cr element.The reaction between austenite phase and medium is easy to form austenitic stainless steel.The three-phase coordination makes the corrosion resistance of the sample much better than304 stainless steel.With the increase of Cr content,the soft magnetic properties of the alloy system are improved significantly.With the increase of amorphous phase and the decrease of austenite phase content,the pinning effect of crystal phase defect and non-magnetic relative domain wall displacement is greatly weakened;with the increase of ferrite phase content,the total number of magnetic domains increases,the number of domain wall displacement increases greatly,the pinning force is small,the ferromagneti sm of ferrite phase is more excellent,and the soft magnetic properties of amorphous steel are greatly improved by synergy with amorphous phase.When the content of Cr is 1 at%,the saturation magnetization is 0.01 T and the maximum coercivity is 102.01 Oe.When the content of Cr is 14 at%,the maximum saturation magnetization is 0.51 T and the lowest coercivity is 16.124 Oe. |
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