2A14铝合金混合表面纳米化对电化学腐蚀行为的影响

发布时间：2018-10-08 12:43

【摘要】：采用超音速微粒轰击(SFPB)和表面机械滚压处理(SMRT)相结合的混合表面纳米化方法,在2A14铝合金上制备出梯度纳米结构(GNS)表层,对比研究了原始样品和常温空气及低温液氮环境下混合表面纳米化样品在3.5%Na Cl水溶液中的电化学腐蚀行为.结果表明:经混合表面纳米化处理后,2A14铝合金晶粒尺寸由最表层约30 nm逐渐增大到基体的原始尺寸,塑性变形层厚度约130 mm,表面粗糙度R_a约为0.6 mm,表面微小裂纹消失.与原始样品相比,经过SFPB处理的样品耐点蚀能力没有得到提高,混合表面纳米化样品的耐点蚀能力得到提高,其中常温空气环境下样品的自腐蚀电位和点蚀击破电位分别由-1.01228和-0.29666 V升高到-0.67445和0.026760 V,耐点蚀能力最强.分析表明,表层晶粒尺寸纳米化、晶界显著增多、残余压应力以及表面粗糙度的改善有利于提高样品的耐点蚀性能.
[Abstract]:The gradient nanostructure (GNS) surface layer was prepared on the 2A14 aluminum alloy by the mixed surface nanocrystalline method of supersonic particle bombarding (SFPB) and surface mechanical rolling treatment (SMRT). The electrochemical corrosion behavior of the original sample and the mixed surface nanocrystalline sample in 3.5%Na Cl aqueous solution at room temperature and low temperature was studied. The results show that after nanocrystalline treatment of mixed surface, the grain size of Al alloy increases gradually from the top layer to the original size of the matrix, and the plastic deformation layer thickness is about 130 mm, and the surface roughness R _ (a) is about 0.6 mm,. Compared with the original samples, the pitting corrosion resistance of the samples treated with SFPB has not been improved, and the pitting corrosion resistance of the mixed surface nanocrystalline samples has been improved. The self-corrosion potential and pitting breakdown potential of the samples increased from -1.01228 and -0.29666 V to -0.67445 and 0.026760 V, respectively, and the pitting resistance was the strongest. The results show that the surface grain size is nanocrystalline, grain boundary is increased significantly, and the improvement of residual compressive stress and surface roughness is beneficial to improve the pitting corrosion resistance of the samples.
【作者单位】：火箭军工程大学;西安理工大学材料科学与工程学院;
【基金】：国家自然科学基金项目51275517 西安理工大学特色研究项目2014TS002资助~~
【分类号】：TG174.4

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