Al元素含量对FeCr1.5NiMnAlx高熵合金熔覆层的影响

Effect of Al element content on FeCr1.5NiMnAlx high entropy alloy cladding layer

  • 摘要:
    目的 旨在研究Al元素对FeCr1.5NiMnAlx (x=1, 1.5, 2)高熵合金熔覆层的组织与性能的影响。
    方法 采用氩弧熔覆的方法在Q235钢上制备了不同Al元素含量的FeCr1.5NiMnAlx高熵合金熔覆层,并对熔覆层的微观组织、物相组成、表面硬度、耐磨性与耐蚀性进行了分析。
    结果 结果表明,FeCr1.5NiMnAlx高熵合金熔覆层组织为枝晶结构,随着Al元素含量的增加,熔覆层的相结构由混合的BCC相+FCC相转变为单一的BCC相。Al元素含量的增加促进了熔覆层中的晶格畸变,并且伴随着金属间化合物的析出,从而提高了熔覆层的硬度和耐磨性。对于耐蚀性而言,熔覆层在质量分数3.5%的NaCl溶液中的腐蚀形式主要为点蚀,随着Al元素含量的提高,熔覆层的自腐蚀电流密度逐渐增大,耐蚀性逐渐减弱。
    结论 Al元素含量的增加导致了相结构由混合的BCC相+FCC相转变为单一的BCC相,且在枝晶间会有条状的硼化物析出。当Al元素摩尔比为2时,硬度最高为51.76 HRC,磨损量几乎为0,此时具有更好的耐磨性。而当Al元素的摩尔比为1时,具有更低的自腐蚀电流密度,在耐蚀性方面有着明显的提升。

     

    Abstract: Objective The aim is to study effect of Al element on microstructure and properties of FeCr1.5NiMnAlx (x = 1, 1.5, 2) high entropy alloy cladding layer. Methods FeCr1.5NiMnAlx high-entropy alloy cladding layers with different Al element content were prepared on Q235 steel by argon arc cladding. Microstructure, phase composition, surface hardness, wear resistance and corrosion resistance of cladding layers were analyzed. Results The results show that microstructure of FeCr1.5NiMnAlx high-entropy alloy cladding layer is dendritic structure. With the increase of Al element content, phase structure of cladding layer changes from mixed BCC phase + FCC phase to single BCC phase. Increase of Al element content promotes lattice distortion in cladding layer and is accompanied by precipitation of intermetallic compounds, thereby improving hardness and wear resistance of cladding layer. For corrosion resistance, corrosion form of cladding layer in 3.5wt.%NaCl solution is mainly pitting corrosion. With the increase of Al element content, self-corrosion current density of cladding layer gradually increases, and corrosion resistance gradually decreases. Conclusion Increase of Al element content leads to transformation of phase structure from mixed BCC phase + FCC phase to single BCC phase, and strip boride precipitates between dendrites. When molar ratio of Al element is 2, hardness is up to 51.76 HRC, and wear loss is almost 0, which has better wear resistance. When molar ratio of Al element is 1, it has a lower self-corrosion current density and a significant improvement in corrosion resistance.

     

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