Effect Of Heat Treatment On The Growth Behavior Of Second Phase Particles In Deformed Zirconium Alloy

Because of the world's appealing to new energy,the state's attention to the nuclear industry,researching and designing the nuclear equipment with independent intellectual property is emergency.Zirconium alloy is used as nuclear reactor structural parts because of its low thermal neutron cross section,excellent corrosion resistance and mechanical properties.However,the zirconium alloys applied in our nuclear industry have been dependent on imports.As a result,researching and exploring the zirconium alloy is a top priority task.In this research,Zr-Sn-Nb-Fe-Cu-Si-O alloy is used for all the experiments.The alloy is cold rolling or hot rolling to plate with a deformation of from 10%to 40%.After that,alloy is heat treated under different temperatures and various processing times.By optical microscope?OM?,scanning electron microscopy?SEM?,electron backscatter diffraction?EBSD?,transmission electron microscopy?TEM?,the growing behavior and micro-hardness of Zr-Sn-Nb-Fe-Cu-Si-O alloy is investigated.The results as follow:?1?By annealing the Zr-Sn-Nb-Fe-Cu-Si-O alloy under different temperature for different time with various deformation,the results show that higher deformation,higher heat treatment temperature and longer annealing time,would lead to a dispersive distribution of second phase partiles.The second phase particles is Zr₂₄Nb₂ Fe₇ with hcp structure.The higher deformation percentage would introduce dislocations,which increased the nucleation sites,and reduced the diameter of SPPs and uniformly distributed SPPs.?2?The micro-hardness of alloy is related to the alloy's deformation,and heat treatment temperatue and time.Higher deformaiton percentage would lead to larger amount of dislocation and defeats,which would increase the alloy's micro-hardness.Recrystallization issued from higher annealing temperature and longer heating time,could harden material.?3?Limited differences of second phase particles could be seen form alloy prepared by cold rolling and hot rolling.The distribution of second phase particles is in line with second order kinetics.However,more dispersive distribution of SPPs couls be obtained by hot rolling.It is proved that when the SPPs'distribution is corresponded with second order kinetics,the mean size of SPPs would tend to be a constant,even the annealing temperature heighten or the time elongated.