激光制备AlxCoCrNiMo高熵合金涂层的研究
Synthesis of AlxCoCrNiMo High Entropy Alloy Coatings by Laser Cladding
1 清华大学机械工程系先进成形与制造教育部重点实验室,北京 100084
2 中国科学院力学研究所,北京 100190
摘要
激光制备高熵合金涂层对于拓展性能优异的高熵合金在表面改性中的应用具有重要意义。采用激光熔覆的方法,在45#钢基体上制备了成形良好的AlCoCrNiMo涂层,证实了激光制备AlCoCrNiMo高熵合金涂层的可行性,并研究了激光熔覆工艺参数和Al含量对AlCoCrNiMo高熵合金涂层的成形质量、微观组织结构、硬度的影响规律。结果表明,在无保护气体、涂覆厚度较薄、能量密度适宜时,可以得到成形质量良好的AlCoCrNiMo高熵合金涂层;涂层组织由共晶体和网状联接物组成,平均硬度在950~1250HV0.2之间,在800℃下仍能保持700HV5的硬度,随着工艺参数的不同,涂层的组织、硬度会有一定的差异;随着Al含量的增加,AlxCoCrNiMo涂层的相结构变得简单,网状联接物的耐腐蚀相减少,硬度降低,但涂层的硬度始终在950HV0.2以上。
Abstract
It is of significance synthesizing high entropy alloys by laser cladding, which means these alloys with outstanding properties can be more widely used in surface modification. The AlCoCrNiMo coating with good formation was synthesized on 45 steel by laser cladding. The influence of technological parameters on the formation, microstructure and properties of the AlCoCrNiMo coating was investigated, so was the influence of the dosage of Al on the AlxCoCrNiMo coating. The results shows, when the thin precoating is synthesized in right energy density without shielding gas, the AlCoCrNiMo clad coating has good formation, the typical microstructure of the AlCoCrNiMo clad coating has two constituents, the eutectic and the vienshaped reinforcement, the hardness of the clad coating is in the range from 950 HV0.2 to 1250HV0.2, and keep 700HV5 at 800℃, these technological parameters have some effect on the microstructure and properties of the clad coating, with the addition of Al in AlxCoCrNiMo, the phases of the alloy become simpler, the amount of the corrosionresistant phase in the vienshaped reinforcement decreases. As a result, the hardness of the clad coating declines, but always above 950HV0.2.
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