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Abstract：
The present work evaluates the effect of Co content on the microstructure and corrosion performance of Al-Co alloys of various compositions (2-32 wt% Co), fabricated by flux-assisted stir casting. A preliminary investigation on the effect of heat treatment (600 °C, up to 72 h) on the microstructure and corrosion behavior of Al-20 wt% Co and Al-32 wt% Co was also conducted. The Al- (2-10) wt% Co alloys were composed of acicular Al9Co2 particles uniformly dispersed in an Al matrix. The Al-20 wt% Co and Al-32 wt% Co alloys additionally contained Al13Co4 blades enveloped in Al9Co2 wedges. Heat treatment of Al-20 wt% Co and Al-32 wt% Co led to a significant reduction in the volume fraction of Al13Co4 and a decrease in hardness. Al-Co alloys with high Co content (10-32 wt% Co) exhibited greater resistance to localized corrosion in 3.5 wt% NaCl, but lower resistance to general corrosion compared to the (0-5 wt% Co) alloys. Heat treatment led to a slight increase in the corrosion resistance of the Al-Co alloys. The microstructure of the produced alloys was analyzed and correlated with the corrosion performance. Finally, corrosion mechanisms were formulated.
摘要：
本工作评估了Co含量对各种成分（2-32wt％Co）的Al-Co合金的微观结构和腐蚀性能的影响，通过焊剂辅助搅拌铸造制造。对热处理效果的初步调查（600°C，长达72h）还对Al-20wt％Co和Al-32wt％Co的微观结构和腐蚀行为进行了研究。Al-（2-10）wt％Co合金由均匀分散在Al基体中的针状Al9Co2颗粒组成。Al-20wt％Co和Al-32wt％Co合金还包含包裹在Al9Co2楔形物中的Al13Co4叶片。Al-20wt％Co和Al-32wt％Co的热处理导致Al13Co4的体积分数显着降低，硬度降低。具有高Co含量（10-32wt％Co）的Al-Co合金在3.5wt％NaCl中表现出对局部腐蚀的更大抵抗力，但与（0-5wt％的Co）合金相比，对一般腐蚀的抵抗力较低。热处理导致Al-Co合金的耐腐蚀性略有增加。分析了所生产合金的微观结构，并将其与腐蚀性能相关联。最后,制定了腐蚀机理。
