A new guide for improving mechanical properties of non-equiatomic FeCoCrMnNi medium-and high-entropy alloys with ultrasonic nanocrystal surface modi?cation process
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2020年第24期
论文作者：Timothy Alexander Listyawan Hyunjong Lee Nokeun Park
文章页码：37 - 43
摘 要：Ultrasonic nanocrystal surface modification （UNSM） treatment on non-equiatomic medium-and highentropy alloy （HEA） of Fex（Co Cr Mn Ni）100-xis firstly introduced and its impact on microstructure and mechanical properties are revealed.By UNSM,severe plastic deformation-induced dislocation and deformation twins （DTs） arise at the topmost surface.Especially,Fe60（Co Cr Mn Ni）40（Fe60）,which is classified as a medium-entropy alloy （MEA）,exhibits ε-martensitic transformation.In the room temperature tensile test,a high strength of～600 MPa and ductility of～65%elongation （strain to failure） is accomplished in Fe60.Initially formed DTs and ε-martensitic transformation by UNSM treatment plays a key role in retardation of necking point via both twinning-induced plasticity and transformation-induced plasticity.However,Fe20（Co Cr Mn Ni）80（Fe20） comparatively shows low strength of～550 MPa and～40%elongation,owing to the low accommodation of DTs than Fe60.Our research will provide new guidelines for enhancing the mechanical properties of MEA and HEA.
Timothy Alexander Listyawan1，Hyunjong Lee2，Nokeun Park1,3
1. School of Materials Science and Engineering, Yeungnam University2. Korea Institute of Industrial Technology3. Institute of Materials Technology, Yeungnam University
摘 要：Ultrasonic nanocrystal surface modification （UNSM） treatment on non-equiatomic medium-and highentropy alloy （HEA） of Fex（Co Cr Mn Ni）100-xis firstly introduced and its impact on microstructure and mechanical properties are revealed.By UNSM,severe plastic deformation-induced dislocation and deformation twins （DTs） arise at the topmost surface.Especially,Fe60（Co Cr Mn Ni）40（Fe60）,which is classified as a medium-entropy alloy （MEA）,exhibits ε-martensitic transformation.In the room temperature tensile test,a high strength of～600 MPa and ductility of～65%elongation （strain to failure） is accomplished in Fe60.Initially formed DTs and ε-martensitic transformation by UNSM treatment plays a key role in retardation of necking point via both twinning-induced plasticity and transformation-induced plasticity.However,Fe20（Co Cr Mn Ni）80（Fe20） comparatively shows low strength of～550 MPa and～40%elongation,owing to the low accommodation of DTs than Fe60.Our research will provide new guidelines for enhancing the mechanical properties of MEA and HEA.
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