放电等离子烧结Fe_(50)Mn_(30)Co_(10)Cr_(10)高熵合金的显微组织演化  

Microstructure Evolution of Fe_(50)Mn_(30)Co_(10)Cr_(10) High-Entropy Alloy Fabricated by Spark Plasma Sintering

作　　者：龙雁[1] 彭亮[1] 张伟华 李贵琦 彭海燕[1] Long Yan;Peng Liang;Zhang Weihua;Li Guiqi;Peng Haiyan(Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic Materials,South China University of Technology,Guangzhou 510640)

机构地区：[1]华南理工大学广东省金属新材料制备与成形重点实验室,广东广州510640

出　　处：《稀有金属》2021年第7期769-777,共9页Chinese Journal of Rare Metals

基　　金：广东省科技计划项目(2015A010105011);广东省自然科学基金面上项目(2021A1515012469)资助。

摘　　要：以金属元素粉末为原料,采用机械合金化(MA)+放电等离子烧结(SPS)法制备Fe_(50)Mn_(30)Co_(10)Cr_(10)高熵合金,研究了烧结温度、烧结压力对Fe_(50)Mn_(30)Co_(10)Cr_(10)高熵合金显微组织和力学性能的影响。结果表明,不同温度下烧结获得的Fe_(50)Mn_(30)Co_(10)Cr_(10)高熵合金均为包含fcc基体相和层片状hcp相的双相高熵合金。随着烧结温度升高,合金的晶粒尺寸不断增大,合金中hcp相和孪晶界的比例也在不断增大,同时硬度和屈服强度在不断降低,塑性持续增加。在1000℃烧结时合金达到最优的综合力学性能,其压缩屈服强度(σ_(0.2))、抗压强度σ_(max)、断裂时的塑性应变(ε_(p))和维氏硬度分别达到878 MPa,2013 MPa,25.0%和HV 315。随着烧结压力的增加,合金的晶粒尺寸增大,孪晶界的比例也不断增多,屈服强度差距不大,塑性却有着明显的提高。烧结压力从50 MPa升高到80 MPa时,屈服强度由791 MPa降低到762 MPa,而断裂时的塑性应变由19.2%升高至26.8%。In recent years,with the continuous development of human society,the existing traditional metals and alloys could not fully meet the needs of human beings,thus promoted the invention and research of various new materials.In the field of metal materials,three new metal materials:bulk amorphous alloys,high-entropy alloys and composite materials have attracted people’s attention because of their excellent properties,and were considered to be the three most potential research directions of metal materials.High-entropy alloys are a new type of multi-principal element alloys,which had better comprehensive properties than traditional alloys,such as high strength,hardness and ductility.With the deepening of researches on high-entropy alloys,a Fe_(50)Mn_(30)Co_(10)Cr_(10)dual-phase highentropy alloy with TRIP(transformation induced plasticity)phenomenon has been developed.Deformation-induced martensitic transformation occured during the deformation,which could remarkably enhance the strength and ductility of the alloy.Melting and casting,powder metallurgy and deposition were three commonly used methods for preparing high-entropy alloys.The most common method used for preparing Fe_(50)Mn_(30)Co_(10)Cr_(10)high-entropy alloy was the casting method.During casting,multiple remelting and post-treatments were required to make the composition uniform and refine the crystal grains.By spark plasma sintering(SPS),a high-performance bulk material with fine grains and homogeneous structure could be obtained.A Fe_(50)Mn_(30)Co_(10)Cr_(10)high-entropy alloy with ultrafinegrained microstructure was prepared by mechanically alloying(MA)and spark plasma sintering using elemental metal powders as raw material.The uniformly mixed elemental powders were high-energy ball milled for 40 h to obtain Fe_(50)Mn_(30)Co_(10)Cr_(10)high-entropy alloy powders,and then the powders were densified on SPS-3.20 MKII spark plasma sintering system.The phase composition,microstructure(grain size,grain orientation and grain boundary characteristics)and mecha

关 键 词：放电等离子烧结(SPS) 力学性能 高熵合金 孪晶 

分 类 号：TG146[一般工业技术—材料科学与工程]