耐腐蚀摩托艇ADC12-0.5La铝合金微观组织及制备

为改善ADC12铝合金的耐腐蚀性能,通过超声熔铸法制备ADC12-0.5La铝合金,并利用光学显微镜、扫描电镜、能谱分析仪、硬度计、浸泡腐蚀试验和电化学工作站研究了T6热处理和稀土La改性对ADC12铝合金的微观组织、硬度和耐腐蚀性能的影响。结果表明,T6态ADC12-0.5La铝合金微观组织明显细化,α-Al尺寸减小,形貌变圆整,共晶Si相和AlFeMnSi相细化为短棒状。相比于ADC12铝合金,T6态ADC12-0.5La铝合金硬度达到117.7HV,提高了26.8%,腐蚀电流密度降低了10.7%,腐蚀电位上升了64.4%,腐蚀速率降低了54.4%,腐蚀表面平坦且光滑,表现为较轻微的晶间腐蚀。T6态ADC12-0.5La铝合金提高了腐蚀电位,Al-La-Cu稀土相阻碍了电子移动,铝合金的耐腐蚀性能得到大幅度提高。

Microstructure and preparation of ADC12-0.5La aluminum alloy for corrosion resistant motor boat

Abstract: To improve the corrosion resistance of ADC12 aluminum alloy, ADC12-0.5La aluminum alloy was prepared by ultrasonic melt casting. The effects of T6 heat treatment and rare earth La modification on the microstructure, hardness and corrosion resistance of ADC12 aluminum alloy were studied by optical microscope(OM), scanning electron microscope(SEM), energy disperse spectrometer(EDS), hardness tester, immersion corrosion test and electrochemical workstation. The results show that the microstructure of ADC12-0.5La aluminum alloy with T6 heat treatment is obviously refined. The size of α-Al decreases, the morphology becomes rounded, and the eutectic Si phase and AlFeMnSi phase are refined into short rod shape. Compared with ADC12 aluminum alloy, the hardness of ADC12-0.5La aluminum alloy with T6 heat treatment reaches 117.7HV, which is increased by 26.8%. The corrosion current density decreases by 10.7%, the corrosion potential increases by 64.4%, the corrosion rate decreases by 54.4%, and the corrosion surface is flat and smooth, which shows slight intergranular corrosion. The corrosion potential of ADC12-0.5La aluminum alloy with T6 heat treatment can be improved, the Al-La-Cu phase will hinder the movement of electron, and the corrosion resistance of aluminum alloy can be improved greatly