Cr_(2)AlC涂层相结构演变对力学性能的影响  

Effect of Phase-Structure Evolution on Mechanical Properties of Cr_(2)AlC Coating

作　　者：袁江淮 王振玉 马冠水 周广学 程晓英[1] 汪爱英[2] YUAN Jianghuai;WANG Zhenyu;MA Guanshui;ZHOU Guangxue;CHENG Xiaoying;WANG Aiying(School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China;Key Laboratory of Marine Materials and Related Technologies,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China)

机构地区：[1]上海大学材料科学与工程学院,上海200072 [2]中国科学院宁波材料技术与工程研究所中国科学院海洋新材料与应用技术重点实验室,宁波315201

出　　处：《金属学报》2023年第7期961-968,共8页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.52025014、52171090和52101109;宁波市自然科学基金项目No.2021J220。

摘　　要：采用电弧复合磁控溅射技术在镍基高温合金基底表面沉积了Cr-Al-C涂层,通过后续热处理获得了高纯Cr_(2)AlC MAX相涂层,研究了Cr_(2)AlC涂层在1073、1123、1173和1223 K退火2 h后的微观结构演变及其对力学性能的影响。利用XRD、SEM和EDS表征了涂层的相结构、表面/截面形貌和元素分布,利用Vickers压痕仪和纳米压痕仪分析了涂层的硬度和韧性等力学性能。结果表明,随着退火温度的升高,Cr_(2)AlC相逐步分解转变为Cr_(2)Al、Cr_(7)C_(3)和Cr_(23)C_(6)相,元素间扩散作用逐渐增强,但相结构演变没有导致涂层/基底界面的失配,且涂层依然能够保持较高的硬度(超过11 GPa)和弹性模量(超过280 GPa)。由于脆性CrC_(x)相的形成和Al元素的扩散,高温退火后涂层的韧性有轻微下降。With the rapid advancements in high-tech aeroengines and gas turbines,surface protective coatings are of increasing interest for enhancing the mechanical and corrosive performances of blade components under harsh high-temperature conditions.Owing to the unique nanolaminate structure,Cr_(2)AlC coating,a typical Cr-Al-C ceramic comprising MAX phases,provides an excellent combination of metallic and ceramic properties,including high-temperature oxidation resistance and superior damage tolerance.In this work,Cr_(2)AlC coatings were achieved on nickel-based superalloy substrates using a hybrid deposition system with a cathodic arc and magnetron sputtering source and subsequent annealing.Particularly,the effect of microstructure evolution on the mechanical properties of Cr_(2)AlC coating was studied under various thermal annealing temperatures of 1073,1123,1173,and 1223 K for 2 h.The phase structure,surface morphology,cross-sectional morphology,and elemental distribution of the coatings were characterized by XRD,SEM,and EDS.The mechanical properties,including the hardness and toughness of the coatings,were tested by nanoindentation and Vickers indentation.The results showed that the Cr_(2)AlC MAX phase was decomposed and transformed into Cr_(2)Al,Cr_(7)C_(3),and Cr_(27)C_(6) phases at higher annealing temperatures,and element diffusion of the coatings was also observed.Moreover,it was noted that the transition in the phase structure did not lead to the misfit of the interface,and the coatings maintained both a high hardness of 11 GPa and elastic modulus of 280 GPa,regardless of the annealing process.The slight decrease in toughness for annealed coatings could be attributed in the formation of brittle chromium carbides and Al element diffusion.Such Cr_(2)AlC MAX phase coatings are promising candidates as protective materials for wide applications in harsh high-temperatures applications.

关 键 词：Cr_(2)AlC涂层 相结构演变 热稳定性 力学性能 GH4169镍基高温合金 

分 类 号：TG178[金属学及工艺—金属表面处理]