Liquid phase cladding of AlxCoCrFeNi high entropy alloys on AISI 304L stainless steel

• Published in: Surface & coatings technology 2020-11, Vol.402, p.126331, Article 126331
• Main Authors: Fereidouni, Mohammad, Sarkari Khorrami, Mahmoud, Heydarzadeh Sohi, Mahmoud
• Format: Article
• Language: English
• Subjects: AISI 304L; Aluminum; AlxCoCrFeNi; Austenitic stainless steels; Ball milling; Body centered cubic lattice; Cladding; Crystal structure; Dilution; Dilution rate; Dual phase steels; Face centered cubic lattice; High entropy alloy; High entropy alloys; Liquid phase cladding; Liquid phases; Microhardness; Microstructure; Morphology; Nickel; Process parameters; Rare gases; Segregations; Stainless steel; Substrates; Tungsten
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2020.126331

AlxCoCrFeNi (x = 0.5, 1, and 1.5) high entropy alloys (HEAs) were synthesized on the AISI 304L stainless steel via liquid phase cladding using a tungsten inert gas (TIG) heat source. To do so, elemental powder mixtures were initially ball-milled and preplaced on the steel substrate followed by TIG surface melting. The process parameters were chosen in such a way that the least possible dilution of the substrate into the clad zone was achieved. It was observed that the dilution rate was dependent on the Al content of the powder mixture. Microstructural assessments revealed that alloying occurred in the initial powder mixture during surface melting and a relatively uniform microstructure was achieved within the clad zone. X-ray diffraction analysis showed that the deposited layer had a dual phase FCC and BCC crystal structure. It was also noticed that increasing of Al content in the HEA raised the volume fraction of BCC/ordered BCC (B2) phase. It also led to a change in the morphology of columnar dendrites to equiaxed ones. Segregations of Al-Ni rich phase and Cr-rich phase at the interdendritic regions were evident in the HEA with low (x = 0.5) and high (x = 1.5) Al content, respectively. The hardness of the clad zone was appreciably dependent on the Al content of the HEA, so that various contents of 0.5, 1, and 1.5 resulted in the microhardness values of 170, 510, and 530 HV0.1, respectively. •AlxCoCrFeNi high entropy alloy is cladded on AISI 304L stainless steel.•Powder mixture is melted by TIG cladding under dilution-controlled condition.•Dual-phase FCC/BCC structure develops in clad rather than intermetallic compounds.•The volume fraction of BCC phase becomes more with increasing the Al content.