NixAlTiCrFeCoCu高熵合金的显微组织与性能

摘要

利用真空电弧炉制备了NixAlTiCrFeCoCu(x=0.5,1.0,1.5,2.0,2.5,3.0)高熵合金,研究了铸态合金的显微组织、压缩性能和耐腐蚀性能.结果表明:此高熵合金的显微组织主要由具有面心立方结构和体心立方结构的固溶体组成,有花瓣状α相、菊花状共晶组织、富铜的晶间组织和富镍相等;随着镍含量增加,花瓣状α相逐渐减少并消失(当x=2.0时),继而出现富镍相;除了NiAlTiCrFeCoCu合金外,其他5种成分合金的屈服强度都高于1.5 GPa,抗压强度约为2 GPa,压缩断口都为脆性断口;x=2.0时高熵合金在H2SO4溶液中的耐腐蚀性能最好;在NaCl溶液中,x=1.5,2.0,3.0时高熵合金的耐腐蚀性能均优于304不锈钢的.%A series of NixAlTiCrFeCoCu (x=0.5, 1.0, 1.5, 2.0, 2.5, 3.0) high entropy alloys were prepared by vacuum arc furnace.The microstructures,compressive property and corrosion resistance of as-cast high entropy alloys were analyzed.The results indicate that the phases of these alloys were mainly composed by solid solution of body-centered cubic structure and face-centered cubic structure.There were four typical cast structures including petal shaped organization(α-phase), chrysanthemum shaped eutectic structure, intergranular organization which is rich of copper and Ni-riched phase.With the increase of Ni content, petal shaped α-phase reduced and even disappeared when x was 2.0, then the Ni-riched phase appeared.The yield strengths of all other alloys were higher than 1.5 GPa and the compressive strengths were about 2 GPa except NiAlTiCrFeCoCu alloy, and the fractures of these high entropy alloys showed brittle fracture.High entropy alloy had the best performance of corrosion resistance in H2SO4 solution when x was 2.0, and the corrosion resistances of high entropy alloys were better than that of 304 stainless steel in NaCl solution when x were 1.5, 2.0 and 3.0.