Cui Xia

Effects of Heat Treatment on Microstructure and Corrosion Behavior of SiCp/Al-6wt%Mg Composites

Abstract The present work investigated the influence of heat treatment (T1, T4, T6 and annealing) on the microstructure related to the interfacial reaction and corrosion behavior of SiC p /Al-6wt%Mg composites prepared by a pressureless infiltration technique. The results show the occurrence of the precipitates of Si, MgA1 2 O 4 and Mg 2 Si as a result of the interfacial reaction between the SiC particle and the matrix of the composites during heat treatment. The precipitates contents ( f ) of the composites correlate with T1, T4, T6 and annealing heat treatment, following the order of f T1 f T4 f T6 f annealing . The precipitates near SiC particles are responsible to pitting corrosion as a degradation mechanism of the composites. The heat treatments carried out on the composites present a significant influence on the corrosion rate ( j corr ). The correlation between j corr and heat treatment shows the characteristic of j corr-ann > j corr-T6 > j corr-T4 > j corr-T1 , which may be attributed to the interfacial reaction precipitates of the composites during heat treatment.

Cl - 浓度对SiC P /Al复合材料电化学腐蚀行为的影响

采用浸泡模拟实验方法、电化学极化和电化学阻抗谱测试技术，研究了Cl - 浓度对SiC P /Al复合材料电化学腐蚀行为的影响。结果表明：SiC P /Al复合材料在Cl - 介质下钝化现象不明显，腐蚀过程主要为点蚀腐蚀。随Cl - 浓度增加，SiC P /Al复合材料腐蚀速率增加，点蚀电位降低，且复合材料的腐蚀过程机制表现为由单纯电荷传递过程机制向电荷传递过程与腐蚀产物扩散共同作用的混合机制转变。电化学阻抗谱随Cl - 浓度增加呈现出2种类型：单一容抗弧类型、高频区容抗弧和低频区一条与实轴呈45°直线（经典Warburg阻抗）组合的复合类型。