丁培培,叶丛望,凌国平.AM60B压铸镁合金前处理表面缺陷的研究[J].表面技术,2008,37(1):8-10,36.
DING Pei-pei,YE Cong-wang,LING Guo-ping.Investigation on Surface Defects Produced in Pretreatment of Die-casting AM60B Magnesium Alloy[J].Surface Technology,2008,37(1):8-10,36 |
| AM60B压铸镁合金前处理表面缺陷的研究 |
| Investigation on Surface Defects Produced in Pretreatment of Die-casting AM60B Magnesium Alloy |
| 投稿时间：2007-11-20 修订日期：2008-02-10 |
| DOI： |
| 中文关键词: AM60B镁合金 压铸 酸洗 表面缺陷 |
| 英文关键词:AM60B magnesium alloy Die casting Acid cleaning Surface defect |
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| 中文摘要: |
| 在对AM60B镁合金轮毂压铸件进行表面耐蚀处理时，发现在前处理酸洗后，表面某些区域会产生黑色条纹状缺陷。采用体视显微观察、金相显微观察、扫描电镜观察和能谱分析，对该现象产生区域的微观组织与成分进行研究，并对其形成机制作了分析。结果表明：压铸件在边缘处存在成分和组织的不均匀现象，这种不均匀是凝固后期的合金在应力作用下产生的裂纹被周围的低熔点成分的富铝金属液补缩后形成的。富铝金属液含有一定含量的低电位Mg元素，在腐蚀环境下与周围组织形成局部原电池，Mg被选择性腐蚀。同时裂纹处存在大量高电位共晶组织，使得周围组织更容易被腐蚀，最终形成黑色条纹状形貌。 |
| 英文摘要: |
| It is found that the surface defect like black stripes appeared in certain surface regions of die-casting wheel hub AM60B magnesium alloy after acid pickling in the anti-corrosion treatment. The microstructure and composition were observed by means of stereomicroscopy, metallomicroscopy and scanning electron microscopy combined with energy spectrum analysis. The formation mechanism of the defect was discussed. The results show that the microstructure and composition on the edge of die casting AM60B magnesium alloy are nonhomogeneous. Such nonhomogeneity is attributed to the crack which originates under stress at later solidification is feeded by surrounding low melting point Al-rich molten metal. Al-rich molten metal contains certain content of low potential element Mg, and local galvanic cell is formed between Mg and ambient composition in corrosive environment. Mg is selective corroded accordingly. The ambient composition around the crack is easier to be eroded for a great deal of high potential eutectic structure existing at the same time crack, ultimately forming the morphology of black stripes. |
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