冷拉拔过程中含稀土铝镁合金的组织与力学性能演变

熔炼制备不同稀土加入量的Al-3.0Mg-xRE(质量分数/%,x=0,0.12,0.31,RE为La+Ce)合金,研究了该合金的显微组织、硬度和拉伸性能在冷拉拔过程中的演变规律。结果表明:冷拉拔过程中,试验合金的晶粒拉长,第二相拉长并破碎成细小粒子,并在晶界和枝晶界处逐渐聚集呈线状分布,Copper{112}〈111〉型变形织构强度逐渐增高;随着变形量的增大,合金的强度呈线性增大,塑性降低,显微硬度增大;适量稀土(0.12%)的加入能够改善合金组织与力学性能,但过量稀土(0.31%)的加入会导致合金中第二相数量和尺寸的增加,从而降低合金的力学性能。冷拉拔后,Al-3.0Mg-0.12RE合金中第二相的长度最小,数量最少,变形织构强度最高,力学性能最优。

金属材料的电偶腐蚀及其防护技术研究进展

金属材料腐蚀现象随处可见,电偶腐蚀是金属材料的一种特殊腐蚀形式,不仅会导致金属材料使用寿命下降,加快金属构件失效,还会引发其他一系列局部腐蚀行为,具有严重的破坏性。针对异种金属材料电偶腐蚀问题介绍了电偶腐蚀基本原理和主要特点;阐述了异种金属材料电偶腐蚀研究进展与常用研究方法,并对电偶腐蚀防护技术进行了总结,提出电偶腐蚀与防护未来可能研究方向;探讨了电磁场作为新型物理防腐技术对金属材料腐蚀行为的影响,提出电磁场在金属材料电偶腐蚀防护方面应用的设想,为电偶腐蚀防护技术研究提供了新方向。

Protection Performance of Plasma Sprayed Al_(2)O_(3)-13 wt%TiO_(2) Coating Sealed with an Organic-inorganic Hybrid Agent

An organic-inorganic hybrid sealing agent was fabricated and used in the plasma sprayed Al_(2)O_(3)-13 wt%TiO_(2)coating,and conventional silicone agent was also used for comparison.Protection performance of the coatings was comprehensively evaluated based on both anti-corrosion and anti-biofouling properties.The results reveal that the sealing treatment is remarkably useful to decrease the porosity of the coating,and the porosity of the coating sealed with the hybrid agent is only 0.035%.Immersion corrosion test and Tafel polarization test reveal that the sealed coating with the hybrid agent exhibits a better corrosion resistance by compared with the coating sealed with silicone agent.The corrosion current density i_(corr) of the hybrid agent sealed coating is only 0.7×10^(-6)A·cm^(-2).Moreover,anti-biofouling tests both in the outdoor analogue hydraulic environment and in the natural marine environment prove that the mentioned novel coating presents a better combination of corrosion resistance and anti-biofouling property by compared with the other coatings,and it could be used as a protection of metal components in the marine environment.

Influence of Heat Treatment on Microstructure and Mechanical Properties of Plasma Sprayed FeCrMoCBY Amorphous Coatings

The changes of the microstructure and the mechanical properties of FeCrMoCBY amorphous coatings prepared by plasma spraying after heat treatment were investigated.300,400,500 and 600℃were selected as the heat treatment temperature,and the crystallization phenomenon occurred after the heat treatment at 600℃.The crystallization products of the coating heat-treated at 600℃were a-Fe and Fe23(C,B)6.Heat treatment was beneficial to the microhardness and the bonding strength of the coatings.The microhardness of the coating heat-treated at 600℃increased obviously,and the strongest bonding strength occurred in the coating heat-treated at 500℃.The improvement of the wear resistance of the coatings could attribute to heat treatment as well,and the wear resistance of the coating heat-treated at 600℃was the optimum,compared with the coating heat-treated at 500℃.

Er对海工5052铝合金腐蚀行为的影响

通过浸泡实验和电化学实验测试了稀土元素Er对海洋工程常用5052铝合金腐蚀行为的影响,通过光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析仪(EDS)观察腐蚀前后合金微观组织形貌与分析腐蚀产物成分。结果表明:随着5052铝合金中稀土Er加入量的增加,合金耐蚀性先升高后降低,Er加入量为0.4%时合金耐蚀性最好。适量Er的加入能够提高5052铝合金的耐蚀性,但过量Er的加入会导致合金耐蚀性大幅度降低。

冷拉拔变形过程中含稀土铝镁合金腐蚀行为研究

采用光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析仪(EDS)、电化学工作站研究了在不同冷拉拔变形量下,Al-3.0%Mg-0.12%RE(质量分数)合金微观组织和腐蚀行为的变化规律,探索了冷拉拔变形量和微观组织对合金耐蚀性的影响。结果表明:随着冷拉拔变形量增加,Al-3.0%Mg-0.12%RE合金中等轴状晶粒向纤维状晶粒转变,晶粒均沿拉拔方向拉长,垂直拉拔方向拉扁,晶界处第二相被拉长并随着晶界的变形逐渐向线状分布。合金点蚀均主要发生在合金中的第二相处,随着冷拉拔变形量的增加,Al-3.0%Mg-0.12%RE合金均匀腐蚀敏感性增强,但点蚀敏感性减弱,阻抗半径增大,耐蚀性变好。

等离子喷涂FeCrMoCBY铁基非晶涂层耐蚀性研究

采用等离子喷涂技术制备了FeCrMoCBY铁基非晶涂层,研究了铁基非晶涂层在3.5%NaCl溶液中浸泡不同时长后的电化学腐蚀性能和微观组织结构。结果表明,在720 h的浸泡期间,涂层的耐蚀性经历了先提高后降低的变化,在浸泡216 h时达到最优,腐蚀电流密度达到最低,为3.393×10^(-5)A·cm^(-2),且此时涂层的表面更加致密,没有明显孔隙。在经过720 h浸泡后,涂层仍能保持在一个相对较低的腐蚀电流密度6.970×10^(-5)A·cm^(-2)。

磁场作用下不同Mg含量Al-Mg合金腐蚀行为研究

通过扫描电子显微镜、能谱分析仪、电化学工作站研究了磁场对不同Mg含量Al-Mg合金腐蚀行为的影响;通过自制磁场装置对氯化钠溶液进行磁化处理,研究磁场对溶液性质的影响。探究磁场对带电粒子的作用和磁场对溶液性质的改变对铝镁合金腐蚀过程的影响差异。结果表明,溶液经过磁场处理后,pH和电导率增加,进而导致合金的腐蚀速率升高。在磁场的作用下,顺磁粒子Al_(ad)^(+)被聚集在合金表面,抑制腐蚀进一步发展,从而降低了铝镁合金的腐蚀速率。磁场对带电粒子的作用大于溶液pH和电导率变化对合金腐蚀行为的影响,因此整体上导致合金腐蚀速率的降低。