600~1000℃退火处理对FCC型Co_(x)FeMnNi_(3-x)合金组织演变及耐蚀性的影响  

Effect of Annealing at 600—1000℃on Microstructure Evolution and Corrosion Resistance of the FCC-type Co_(x)FeMnNi_(3-x)Alloys

作　　者：吴长军 朱付成[1] 王权 彭浩平 刘亚 苏旭平[1,2] WU Changjun;ZHU Fucheng;WANG Quan;PENG Haoping;LIU Ya;SU Xuping(Jiangsu Key Laboratory of Materials Surface Science and Technology,School of Materials Science and Engineering,Changzhou University,Changzhou 213164,Jiangsu,China;Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering,Changzhou University,Changzhou 213164,Jiangsu,China)

机构地区：[1]常州大学材料科学与工程学院,江苏省材料表面科学与技术重点实验室,江苏常州213164 [2]常州大学光伏科学与工程江苏协同创新中心,江苏常州213164

出　　处：《材料导报》2024年第18期200-206,共7页Materials Reports

基　　金：国家自然科学基金(52271005,51771035);江苏省研究生科研与实践创新计划项目(SJCX23_1479)。

摘　　要：在CoCrFeMnNi合金及不锈钢中,Cr对合金的耐蚀性起到关键作用,但目前对无Cr的Co-Fe-Mn-Ni合金的组织演变及耐蚀性影响的研究较少。本工作使用电弧熔炼法制备了一系列FCC型Co_(x)FeMnNi_(3-x)合金,并在600℃、800℃、1000℃真空退火120 h,实验研究不同退火温度下Co_(x)FeMnNi_(3-x)合金的组织演变及耐蚀性变化规律。结果表明,铸态下这些合金均为枝晶组织,Co含量的增加使得枝晶更加发达。合金的耐蚀性随着Co含量的增加(Ni含量的降低)而逐渐降低。600℃退火后,合金组织整体仍为编织网状枝晶,但枝晶明显淡化,开始向等轴晶演变,晶粒间距增大,耐蚀性降低。600℃退火后的Co_(1.0)FeMnNi_(2.0)合金自腐蚀电流密度(2.19×10-^(6)A·cm^(-2))比铸态时提高了一倍。800℃退火后,Co_(1.0)FeMnNi_(2.0)合金的组织由大量等轴晶组成,其余合金组织仍有枝晶未完全消退。较为稳定的等轴晶使得合金的耐蚀性能提升,自腐蚀电流密度降低至0.68×10^(-6)A·cm^(-2)。退火温度提高到1000℃,合金完全由粗大的等轴晶组成,晶粒间结合紧密。1000℃退火后,Co_(1.0)FeMnNi_(2.0)合金自腐蚀电流密度为0.22×10^(-6)A·cm^(-2),拥有比304L不锈钢更高的耐蚀性。Element Cr plays a critical role in the corrosion resistance of the CoCrFeMnNi alloy and stainless steel.However,there are few studies on microstructure evolution and corrosion resistance of the Cr-free Co-Fe-Mn-Ni alloys.In the present work,a series of Co_(x)FeMnNi_(3-x)alloys,with single FCC phase,were prepared by arc melting method and vacuum annealed at 600℃,800℃,and 1000℃for 120 h,respectively.The microstructure evolution and corrosion resistance of these alloys at different states were investigated.The results show that all the as-cast Co_(x)-FeMnNi_(3-x)alloys are composed of dendrites structure,which developed with Co content.The corrosion resistance of the as-cast alloys decreases with the increase of Co content(the decrease of Ni).After 600℃annealing,the alloy is still braided network dendrite.But the dendrite obviously weakens and begins to evolve to equiaxed grain.The grain boundary coarsened and the corrosion resistance reduced.The corrosion current density of 600℃annealed Co_(1.0)FeMnNi_(2.0)alloy(2.19×10^(-6)A·cm^(-2))becomes twice than that of the as-cast state.After 800℃annealing,the Co_(1.0)FeMnNi_(2.0)alloy is composed of many equiaxed grains,while the other alloys still contain some dendrites.The stable equiaxed grain improves the corrosion resistance of the alloy,and the corrosion current density decreases to 0.68×10^(-6)A·cm^(-2).When the annealing temperature increases to 1000℃,the alloy is totally composed of coarse equiaxed grains,and the grains are closely bonded.The corrosion current density of 1000℃annealed Co_(1.0)FeMnNi_(2.0)alloy decreases to 0.22×10^(-6)A·cm^(-2),which is better than that of 304L stainless steel.

关 键 词：电弧熔炼 退火 高熵合金 显微组织 耐蚀性 

分 类 号：TG113.12[金属学及工艺—物理冶金]