Study On The Diffusion Behavior Of Al/Fe And The Surface Quality Of Mirror Pure Fe

Research on high pressure equation of state,get regular understanding and physical data base has very important value in application,which in modern materials science,astrophysics,especially in inertial confinement fusion?Inertial confinement fusion,ICF?,space technology,planetary physics,geophysics,hot dense plasma physics,physics of high energy density weapons physics,energy engineering and many other applications in the field of science.Traditional measurement methods of high pressure material shock compression line mainly has 3 basic types:flyer impact method?block?,the impedance matching method?comparison method?and the free surface velocity method.In the three methods of measurement material shock compression line,flyer impact method and the free surface velocity method are absolute measurement,the impedance matching method is a relative measurement.If have accurate determination of a material shock compression line,put a"standard"as this material,by comparing the measured,to simplify the other materials measurements,only measured the shock wave velocity by which through the standard material and other materials,because it avoids technology challenges when measure the particle velocity or flyer velocity,so it greatly simplifies the measurement work.Need to prepare the high precision impedance matching target by using the impedance matching method.Because of the advantages of vacuum diffusion bonding method,optimization of diffusion process can prepare the qualified targets.This subject provide the basic data for prepare high precision Al/Fe,Fe/Mo etc target through 2 experiments,respectively:?1?The experiment of Al/Fe vacuum diffusion bonding.The constant heating temperature was 460?,the constant pressure was 9.8MPa,vacuum degree better than10-4Pa,insulation time were:30min,60min,180min,360min and 540min,by used scanning electron microscopy?SEM?and EDS analysis the morphology of diffusion layer and element distribution,indicated that:thermal insulation 30min Al/Fe found no obvious diffusion layer,diffusion from the beginning of Al to Fe.Analysed simples diffusion interface which insulation time were 180min,360min,540min by SEM,found obvious diffusion layers,and used the EDS line scan analysed the distribution of element concentration of diffusion interface layer,the comprehensive analysis indicated that the interface diffusion layer has 3 divisions,respectively:the transition zone of Al side,the intermediate diffusion zone,the transition zone of Fe side.Al,Fe atomic ratio of intermediate diffusion layer was closed 5:2,maybe created Fe₂Al₅.Diffusion layer growth like this:1,Al atoms to Fe side diffusion,forming a heave on the Fe side,along with the Al atoms sustained diffusion,and Fe side's Fe atoms diffusion to heave,and heaves grew up,showing a"bamboo"on the Fe side,there were gaps between“bamboos”,Al side was no obvious heaves,diffusion layer connected into one piece;2,"bamboo"grew up to a certain extent,to the lateral growth,"bamboos"were connected with each other;3,insulation time continued to increase,the diffusion layer to the Fe side bulge forming"bamboo"again,then longitudinal growth.The thickness of the diffusion layer increased with the prolongation of time.?2?Mirror pure Fe annealing experiment.The experimental equipment with the same of diffusion experiment.Using confocal white light interferometer detection performance morphology and roughness,metallographic microscope observation of the surface microstructure,scanning electron microscope?SEM?observation of the surface recrystallized fine grains,XRD detection grain orientation.Analysis shows that:insulation 30min,the heating temperature were below 550?,temperature on the Fe surface roughness were less affected,but it had increasing trend with increased the temperature.The constant heating temperature was 400?,insulation time from 30 to 270min,surface roughness changed very little,in the temperature of 400?,there was basic no effects of insulation time on the surface roughness,grain size did not change significantly.The constant insulation time was 60min,at high temperatures,temperature respectively:810?,860?,885?and 895?,the surface roughness of Fe increased gradually,the maximum was 44nm,but when the temperature was increased to 912?,the sample surface roughness mutated into the 700nm,the analysis was due to polymorphism changes of Fe caused by the volume changed,made undulation surface due to compression between grains,the deeper grain boundary made the roughness increased,at 960?,1020?,1060?three temperature points,Fe surface roughness changed slowly,stable at about 750nm.Recrystallization grains occurs in the local grain boundary began at 810?,caused by the fine recrystallization grains,860?and 885?occurred recrystallization,XRD graphs show that 860?had preferred orientation of grains,grain preferred orientation were more serious when the temperature beyond the phase transition point.Hot pressure mirror pure Fe when heated to 810?,insulation 60min,pressure from 4.8to 19.2MPa,thickness deformation rate increased with the pressure increasing,pure Fe partial recrystallization caused material softening.