Effect Of Sintering Temperature And Holding Time On Structure And Properties Of ODS Alloy

Fusion reactors are the technology of choice for future nuclear plants.The first wall material of the reactor is subject to harsh high temperature,corrosion and radiation conditions.To improve the performance of the first wall material,ODS alloys have emerged.The excellent properties of ODS alloys come from their unique microstructure,including fine grain,high density,nano-oxide precipitation phase.This microstructure is determined by the manufacturing process.To explore the different process parameters on the microstructure and properties of ODS alloys is extremely important.Different process routes or different process parameters have a profound impact on the formation of nanostructured precipitates of ODS alloys.In this paper,the ODS alloys of Y-Al system for the study is prepared by mechanical alloying Fe-9Cr-1.5W-0.24Al-0.5Y2O3(wt.%)supersaturated alloy powder.Using discharge plasma sintering process,Experiments are performed at a sintering temperature of 950?,1000?,1050 ?,1100 ?,1150? and 1200 ? respectively,determine the best sintering temperature.Basing on the determination of the optim?m sintering temperature,the holding time of 5 min,10 min,15 min,20 min is explored,determine the best holding time.Use Nitrox analyzer,Particle size analyzer,XRD,Scanning electron microscope,Transmission electron microscope analysis means.Observe the appearance and determine the ingredients for mechanically alloyed powders and sintered samples prepared.The particle size of the powder,the size of the crystal grains,the density and the size of the precipitated phase are measured.Material density,hardness,tensile strength are measured.Effect of different sintering temperature and holding time on microstructure and properties of ODS alloy are studied.Concluded as follows:(1)ODS alloy are prepared by mechanical alloying and spark plasma sintering,Its density reaches more than 96%,the maxim?m density up to 98.6%;(2)In different sintering temperatures,the size of the grains and precipitates first decreases and then increases with the increase of temperature.When the sintering temperature is 1150?,the minimum size of the grains is 200 nm and the minimum size of precipitates is 6.5 nm;(3)ODS alloy with a sintering temperature of 1150 ? has a hardness of 595 HV and a tensile strength of 802.85 MPa;(4)In different holding time,the size of the grains and precipitates decreases first and then increases with the holding time increasing.The minimum size of the grains is 168 nm when the holding time is 10 min.The minimum size of precipitates is 4.7 nm;(5)ODS alloy holding time of 10min has a hardness of 632 HV and a tensile strength of 863.48 MPa.