摘要
在合金材料领域,实现强度和韧性的同步提升是一个重要的课题。本工作选用CoCrFeNi和AlCoCrFeNi两种异质高熵合金材料,通过精心的结构设计和激光工艺优化,成功制备了一种外硬内韧的新型高熵合金梯度涂层。该涂层具有原位形成的双相界面层,其微观结构从顶部到底部依次为单相体心立方(BCC)、BCC/面心立方(FCC)双相、单相FCC,形成了独特的相梯度结构。硬度测试显示,涂层的硬度从顶部的530HV 0.2递减至中部的350HV 0.2,再至底部的200HV 0.2,这一梯度变化与BCC相含量的减少趋势一致。摩擦性能测试结果表明,这种梯度涂层展现出卓越的耐磨性能,摩擦系数为0.51,磨损率低至4.8×10^(-5) mm^(3)/(N·m),磨损机理主要为粘着磨损。此外,拉伸试验证实了涂层不仅具有出色的抗拉强度,还具备良好的延展性。这种优异的力学性能得益于涂层中双相界面层的生成,该界面层缓解了高硬度层与高韧性层之间的结构和性能差异,减少了应力集中,从而稳定了涂层的整体结构。综上所述,本工作不仅为开发具有综合强度和韧性的新型高熵合金涂层提供了新的方法和理论,还可用于指导类似高熵合金梯度涂层结构的开发和设计,具有重要的应用价值。
In the field of alloy materials,achieving a simultaneous enhancement of strength and toughness is an important topic.This study selected CoCrFeNi and AlCoCrFeNi two heterogeneous high-entropy alloy materials,and successfully prepared a new type of high-entropy alloy gradient coating with an outer hard and inner tough structure through careful structural design and laser process optimization.The coating had an in-situ formed dual-phase interface layer,with its microstructure transitioning from a single-phase body-centered cubic(BCC)at the top,to a BCC/face-centered cubic(FCC)dual-phase in the middle,and finally to a single-phase FCC at the bottom,forming a unique phase gradient structure.Hardness tests showed that the hardness of the coating decreased from 530HV 0.2 at the top to 350HV 0.2 in the middle,and then to 200HV 0.2 at the bottom,which was consistent with the trend of decreasing BCC phase content.Friction performance tests indicated that this gradient coating exhibited excellent wear resistance,with a friction coefficient of 0.51 and a wear rate as low as 4.8×10^(-5) mm^(3)/(N·m),with the primary wear mechanism being adhesive wear.Additionally,tensile tests confirmed that the coating had excellent tensile strength and also good ductility.These excellent mechanical properties could be attributed to the formation of the dual-phase interface layer within the coating,which effectively alleviated the structural and property differences between the high-hardness layer and the high-toughness layer,reduced stress concentration,and thereby stabilized the overall structure of the coating.In summary,this study not only provides new methods and theories for the development of new high-entropy alloy coatings with comprehensive strength and toughness but also can be used to guide the development and design of similar high-entropy alloy gradient coating structures,which is of significant application value.
作者
董照帅
李新梅
贾黎明
贾海洋
闫芷琪
巫理平
DONG Zhaoshuai;LI Xinmei;JIA Liming;JIA Haiyang;YAN Zhiqi;WU Liping(School of Materials Science and Engineering,Xinjiang University,Urumqi 830047,China)
出处
《材料导报》
北大核心
2025年第24期149-155,共7页
Materials Reports
基金
国家自然科学基金(52161017,52561022)
新疆维吾尔自治区自然科学基金(2022D01C386)。
