等离子熔覆法制备AlxCoCrFeNi高熵合金微观组织与性能研究

利用等离子熔覆法在Q235基体上制备了Al_xCoCrFeNi(x=1、1.5,x为摩尔分数)高熵合金,对熔覆层的化学成分、相结构、微观组织和显微硬度进行了研究。结果表明:熔覆态高熵合金具有简单的固溶体结构,微观组织为树枝晶,Al含量从x=1增加到x=1.5时,物相组成由FCC+BCC两相转变为单一的BCC相;当x=1.5时,枝晶间有纳米级颗粒析出;Al_(1.5)CoCrFeNi熔覆层与基体呈现良好的冶金结合,界面附近的热影响区由于珠光体脱碳分解而形成了约为80μm宽的铁素体带;随着Al含量的增加,熔覆层的显微硬度从x=1时的478HV增加到x=1.5时的530HV。

Microstructure and Properties of AlxCoCrFeNi High-entropy Alloys Prepared by Plasma Cladding

The AlxCoCrFeNi(x=1,1.5,x is mole fraction) high-entropy alloys cladding layers were prepared on Q235 steel substrate by plasma cladding.The component,crystal structure,microstructure and microhardness of the cladding layers were investigated.The results indicated that high-entropy alloys cladding layers had simple solid-solution structure.The content of aluminum increased from x =1 to x =1.5,and the phase composition transformed from the mixed FCC+BCC phase to the single BCC phase.The microstructure of cladding layers is dendrite structure.When x =1.5,the nanoparticles were deposited in the dendrite.Al1.5-CoCrFeNi alloy had a good metallurgical combination with the substrate.A ferrite band with width about 80 μm was appeared at HAZ near the interface which was caused by decarburizing of pearlite.With the addition of aluminum changed from x =1 to x =1.5,the microhardness of cladding layers increased from 478HV to 530HV.