铝基可磨耗封严涂层的动态压缩力学行为

Dynamic Compressive Behaviors of Aluminum-Based Abradable Seal Coatings

摘要:

以大气等离子喷涂制备的铝硅-氮化硼和铝硅-聚苯酯可磨耗封严涂层为材料,利用XRD、OM、SEM、准静态压缩、动态压缩等手段,研究了两种铝基封严涂层的微观组织及其在不同应变率下的压缩性能和损伤特征。结果表明,铝硅-氮化硼和铝硅-聚苯酯涂层主要由α-Al固溶体相、共晶Si相、可磨耗第二相(氮化硼/聚苯酯)以及孔隙组成；准静态及动态加载下两种涂层的真应力-真应变曲线均未出现明显的屈服平台,铝硅-氮化硼涂层的动态抗压强度高于铝硅-聚苯酯涂层；动态加载下涂层内部颗粒发生剧烈变形,主要损伤方式为颗粒间界面的脱粘开裂以及内部缺陷处裂纹的萌生及扩展。

Abstract:

Two kinds of aluminum-based abradable seal coatings (AlSi-hBN and AlSi-PHB) were prepared by atmospheric plasma spraying. XRD, OM, SEM, quasi-static and dynamic compression tests were utilized to research the microstructure, compressive properties under different strain rates and relevant damage characteristics of the seal coatings. The results indicated that AlSi-hBN and AlSi-PHB seal coatings were mainly composed of α-Al solid solution phase, eutectic Si phase, abradable second phase (hBN/PHB) and pores. No obvious yield platform was observed on compressive true stress-true strain curves of two coatings under both quasi-static and dynamic loading conditions. The dynamic compressive strength of AlSi-hBN coating was higher than that of AlSi-PHB coating. Particles inside the coatings were severely deformed under dynamic loading. The main damage forms were debonding and cracking at the interparticle interface as well as initiation and propagation of cracks at the internal defects.