选区激光熔化成形Fe-Mn-Cr-Ni中熵合金的缺陷类型及形成机理  

Defect Types and Formation Mechanism of Fe-Mn-Cr-Ni Medium Entropy Alloys Formed via Selective Laser Melting

作　　者：杜晓洁 易铄 徐震霖 何宜柱 Du Xiaojie;Yi Shuo;Xu Zhenlin;He Yizhu(School of Materials Science and Engineering,Anhui University of Technology,Ma’anshan 243032,Anhui,China;Anhui Key Laboratory of Metal Material and Processing,Ma’anshan 243032,Anhui,China)

机构地区：[1]安徽工业大学材料科学与工程学院,安徽马鞍山243032 [2]安徽省金属材料与加工重点实验室,安徽马鞍山243032

出　　处：《激光与光电子学进展》2024年第21期297-305,共9页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(51271001);安徽省科技重大专项资助项目(2020a05020038)。

摘　　要：基于选区激光熔化制备了Fe-Mn-Cr-Ni中熵合金,通过改变激光功率和扫描速度,对不同体能量密度样品的缺陷和表面质量进行研究。研究结果表明:随着体能量密度上升,样品的致密度呈现出先上升后降低的趋势,表面粗糙度则表现为先减小后增大。在体能量密度较低(≤77.38 J/mm^(3))的情况下,合金表面的粉末因未充分熔化而烧结在一起,在表面形成凸起,其内部缺陷主要是粉末未熔合导致的球化缺陷;在体能量密度较高(≥104.76 J/mm^(3))的情况下,成形过程中产生的熔滴飞溅并堆积在样品表面,在合金内部发生匙孔效应并诱导产生微裂纹。与此同时,成形块体的硬度也随着体能量密度的增加呈现出先升高后降低趋势。体能量密度为88.44 J/mm^(3)的样品具有最高的致密度(99.5%)和最好的成形质量,其维氏硬度为211 HV,抗拉强度为549 MPa,延伸率为21.8%。In this study,a Fe-Mn-Cr-Ni medium entropy alloy is fabricated using selective laser melting.By varying the laser power and scanning speed,the surface imperfections and quality of the alloy samples with different energy density are evaluated.The result shows that as the bulk energy density increases,the relative density of the samples initially increases and then decreases,whereas the surface roughness initially decreases and then increases.Under a low bulk energy density(≤77.38 J/mm^(3)),the powder on the alloy surface is sintered together owing to insufficient melting,thus resulting in a protruded surface.The main internal defects are spheroidization defects caused by powder non-fusion.Under a high bulk energy density(≥104.76 J/mm^(3)),the droplets generate during the forming process splash and accumulate on the surface of the sample,thus causing a keyhole effect within the alloy and inducing microcracks.The hardness of the formed block first increases and then decreases as the bulk energy density increases.The sample with a bulk energy density of 88.44 J/mm^(3)exhibits the highest relative density(99.5%)and superior forming quality.Additionally,it exhibits as Vickers hardness of 211 HV,a tensile strength of 549 MPa,and an elongation of 21.8%.

关 键 词：中熵合金 选区激光熔化 体能量密度 致密度 成形缺陷 

分 类 号：TG457.1[金属学及工艺—焊接]