热处理对SiCp/Al-6%Mg复合材料微观组织及腐蚀行为影响

Effects of heat treatment on microstructure and corrosion behavior in SiCp/Al-6%Mg composites

摘要:

采用无压渗透法制备了SiC_p/Al-6%Mg复合材料,并对其进行4种热处理工艺(T1, T4, T6和退火)处理,研究了热处理工艺对SiC_p/Al-6%Mg复合材料微观组织和腐蚀行为的影响。结果表明,复合材料在4种热处理工艺下均出现了界面反应产物Si、MgA1₂O₄ 和 Mg₂Si。界面反应产物析出量(f)与热处理工艺密切相关,并呈现出如下规律：f_T1< f_T4< f_T6annealing。界面反应析出物是导致复合材料发生点蚀的主要原因,从而促进复合材料发生腐蚀。热处理工艺能影响界面反应析出量而间接影响复合材料的腐蚀速度(j_corr)：j_corr-T6> j_corr-T4> j_corr-T1。

Abstract:

The present work examines the influence of heat treatment on the microstructure related to the interfacial reaction and corrosion behavior of SiC_p/Al-6%Mg composites prepared by using a pressureless infiltration technique. The experimental results show the occurrence of the precipitates of Si, MgA1₂O₄ and Mg₂Si as a result of the interfacial reaction between the SiC particle and matrix of the composites during heat treatment. The precipitates contents(f) of composites are correlated with T1, T4, T6 and annealing heat treatment, following the order of f_T1< f_T4< f_T6annealing. The precipitates located 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 present the characteristics of j_corr-ann> j_corr-T6> j_corr-T4> j_corr-T1, which may be attributed to the the interfacial reaction precipitates of the composites during heat treatment.