AlCr_(1.3)TiNi_(2)共晶高熵合金的高温摩擦学性能及磨损机理  

Tribological Properties and Wear Mechanism of AlCr_(1.3)TiNi_(2)Eutectic High-Entropy Alloy at Elevated Temperature

作　　者：苗军伟 王明亮 张爱军[3] 卢一平[1,2] 王同敏[2] 李廷举[2] MIAO Junwei;WANG Mingliang;ZHANG Aijun;LU Yiping;WANG Tongmin;LI Tingju(Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province),School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,China;Engineering Research Center of High Entropy Alloy Materials(Liaoning Province),School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,China;Key Laboratory of Science and Technology on Wear and Protection of Materials,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]大连理工大学材料科学与工程学院、辽宁省凝固控制与数字化制备技术重点实验室,大连116024 [2]大连理工大学材料科学与工程学院、辽宁省高熵合金材料工程研究中心,大连116024 [3]中国科学院兰州化学物理研究所、中国科学院材料磨损与防护重点实验室,兰州730000

出　　处：《金属学报》2023年第2期267-276,共10页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.51822402、U20A20278和52001051;国家重点研发计划项目Nos.2018YFA0702901和2019-YFA0209901;辽宁省兴辽英才计划项目No.XLYC1807047;宁波市“科技创新2025”重大专项项目No.2019B10086;中国博士后科学基金项目No.2021T140082。

摘　　要：采用电磁悬浮熔炼+直接铸造的方法制备了千克级的AlCr_(1.3)TiNi_(2)共晶高熵合金,借助TEM、APT等表征手段分析了该合金的微观组织与成分分布,使用HT-1000摩擦试验机对比研究了该合金与GH4169镍基高温合金的高温摩擦学性能。结果表明:该共晶高熵合金具有超细的层片状共晶组织(层片间距约350 nm),其共晶两相为晶格错配度只有约2%的bcc相与L2_(1)相,L2_(1)相中还存在大量的纳米析出相;≤600℃时,共晶高熵合金的磨损机理以磨粒磨损为主,其磨损率均低于GH4169合金;800℃时,共晶高熵合金的磨痕表面塑性变形加剧,其摩擦系数明显高于GH4169合金,但2者的磨损率相差不大。GH4169合金高温耐磨性的提高得益于其磨损表面氧化物膜的形成,而共晶高熵合金出色的耐磨性主要与其良好的高温组织稳定性及力学性能有关。Eutectic high-entropy alloys(EHEAs)have been explored as possible options for hightemperature applications due to their controlled microstructure and excellent mechanical properties.In particular,EHEAs possess good liquidity and castability,allowing their possibility for real-size industrial manufacturing.However,despite their importance as a structural material index,the tribological properties were rarely investigated in the EHEAs field.In this study,a kilogram-scale AlCr_(1.3)TiNi_(2)EHEA was produced using electromagnetic levitation melting and direct casting approach.The EHEA's microstructure and chemical composition were investigated using a TEM and APT techniques.The AlCr_(1.3)TiNi_(2)EHEA's tribological properties were examined from room temperature to 800℃using a rotational ball-on-disk tribometer(HT-1000).Meanwhile,for comparison,a GH4169 nickel-base superalloy was chosen.The corresponding wear mechanisms were also thoroughly discussed.The findings exhibit that the as-cast AlCr_(1.3)TiNi_(2)EHEA,which had an ultrafine lamellar structure,consisted of a disordered bcc phase and an ordered L2_(1)phase with lattice misfit of approximately 2%.The average interlamellar spacing was about 350 nm.Additionally,a large number of nanoprecipitates contains in the L2_(1)lamellae central region.Below 600℃,the AlCr_(1.3)TiNi_(2)EHEA's primary wear mechanism was abrasive wear,and its wear rate was lower than that of the GH4169 alloy.At 800℃,distinct plastic deformation features were observed on the worn surface of EHEA.The EHEA exhibited a much higher friction coefficient than that of the GH4169 alloy at 800℃,but their wear rates were similar.The wear resistance improvement of GH4169 alloy at high temperature was ascribed to the formation of oxide film on its worn surface,and the AlCr_(1.3)TiNi_(2)EHEA's excellent wear resistance mainly resulted from good structure stability and high hot hardness.Current findings offer new insights into the industrial application of EHEA in high-temperature fields.

关 键 词：高熵合金 摩擦磨损 高温合金 共晶组织 高温 

分 类 号：TG139[一般工业技术—材料科学与工程]