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Complex concentrated alloy bimodal composite claddings with enhanced cavitation erosion resistance
Surface & Coatings Technology ( IF 5.4 ) Pub Date : 2020-04-08 , DOI: 10.1016/j.surfcoat.2020.125751
H.S. Grewal , R.B. Nair , H.S. Arora

In this current study, we developed SiC (10 wt%) reinforced AlCoCrFeNi complex concentrated alloy composite claddings with different particle sizes (micro, nano and bimodal) on stainless steel 316L substrate using microwave irradiation. Microstructural analysis showed cellular structured claddings with intermetallic phases occupying the intercellular regions along with low porosity (<1%). The claddings were mainly composed of A2 (disordered BCC) and B2 (ordered BCC) along with Cr23C6. The bimodal (mixture of nano and micro) composite cladding showed highest hardness and fracture toughness (810 HV and ~12.2 MPa√m) followed by nano and micro composite claddings. Under cavitation erosion (distilled water) condition, bimodal cladding showed highest incubation period (IP) (~13 h) with extremely low mean depth erosion rate (MDER) (~0.089 μm/h) with 16 and 27 times lower than stainless steel 316L and WC-based coating, respectively. The cavitation erosion resistance observed for the bimodal composite cladding is among the highest demonstrated by the CCAs at present. However, under erosion-corrosion conditions, non-reinforced and micro-reinforced claddings showed higher degradation resistance with lower material removal rates than that observed for bimodal cladding. Standalone electrochemical corrosion studies also showed highest corrosion and passivation resistance for non-reinforced cladding. These results were explained on the basis of formation of Cr-depleted micro-galvanic cells due to high negative enthalpy of Cr with C dissociated from SiC particle. The detailed morphological analysis of the tested samples showed presence of tearing top surface as the primary degrading mechanism along with fracture of intermetallic phases. The results show that bimodal composite CCA cladding provides a potential surface engineering solution for improvising the serviceability of the many engineering systems.



中文翻译:

复杂的浓合金双峰复合熔覆层,具有增强的抗空蚀性

在本研究中,我们使用微波辐射在316L不锈钢基底上开发了具有不同粒径(微米,纳米和双峰)的SiC(10重量%)增强的AlCoCrFeNi复杂浓缩合金复合熔覆层。显微组织分析表明,具有金属间相的细胞结构包层占据了细胞间区域,且孔隙率低(<1%)。包层主要由A2(无序BCC)和B2(有序BCC)以及Cr 23 C 6组成。双峰(纳米和微米的混合物)复合覆层具有最高的硬度和断裂韧性(810 HV和〜12.2MPa√m),其次是纳米和微米的复合覆层。在空化侵蚀(蒸馏水)条件下,双峰熔覆层的潜伏期(IP)最高(〜13 h),平均深度侵蚀率(MDER)极低(〜0.089μm/ h),比316L不锈钢低16倍和27倍和基于WC的涂层。目前,双峰复合覆层的抗气蚀性能是CCA所证明的最高。但是,在腐蚀腐蚀条件下,与双峰熔覆层相比,非增强熔覆层和微增强熔覆层显示出更高的抗降解性和更低的材料去除率。独立的电化学腐蚀研究还显示出非增强覆层具有最高的抗腐蚀和钝化性能。这些结果是基于由于Cr的负负焓和从SiC颗粒中解离的C导致的Cr耗尽的微原电池的形成而解释的。对测试样品的详细形态分析表明,存在撕裂的上表面作为主要的降解机理以及金属间相的断裂。结果表明,双峰复合CCA覆层为改善许多工程系统的可服务性提供了潜在的表面工程解决方案。这些结果是基于由于Cr的负负焓和从SiC颗粒中解离的C导致的Cr耗尽的微原电池的形成而解释的。对测试样品的详细形态分析表明,存在撕裂的上表面作为主要的降解机理以及金属间相的断裂。结果表明,双峰复合CCA覆层为改善许多工程系统的可服务性提供了潜在的表面工程解决方案。这些结果是基于由于Cr的负负焓和从SiC颗粒中解离的C导致的Cr耗尽的微原电池的形成而解释的。对测试样品的详细形态分析表明,存在撕裂的上表面作为主要的降解机理以及金属间相的断裂。结果表明,双峰复合CCA覆层为改善许多工程系统的可服务性提供了潜在的表面工程解决方案。

更新日期:2020-04-08
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