【摘要】 采用室温拉伸、晶间腐蚀、电化学极化曲线等实验手段,环境扫描电子显微镜(SEM)、能谱分析(EDS)、透射电子显微镜(TEM)等现代分析测试方法,研究在Mg、Si质量比固定不变时,改变Mg、Si含量对Al-Mg-Si合金显微组织、力学性能与腐蚀性能的影响。结果表明,Mg、Si含量(质量分数)分别从0.6%和0.56%增大到1.6%和1.49%时,晶内β″强化相的密度增大,使得合金的力学性能呈增强趋势。当合金含量继续增大,晶内β″相密度增大不明显,但晶界上MgSi相粗化且出现在晶内,在合金受力断裂时脆性的MgSi相相连直接形成裂纹,使力学性能下降。Mg、Si含量的增大会导致合金的耐腐蚀性能不断下降,这是因为腐蚀先发生在第二相或第二相周围的基体,而合金元素增多将使晶界及晶内出现更多第二相,使腐蚀更容易发生。更多还原

【Abstract】 The effect of Mg and Si content with fixed Mg/Si ratio on the microstructure and properties of Al-Mg-Si alloy was investigated by mechanical properties testing, intergranular corrosion and electrochemical polarization curve, combined with SEM, EDS, TEM techniques. The experimental results indicate that increasing content of Mg and Si from 0.6 wt% and 0.56 wt% to 1.6 wt% and 1.49 wt% can improve mechanical property by promoting the precipitation of metastable β″ precipitates. Continuing to increase the content of Mg and Si can coarsen the MgSi phase which would crack easily under stress and lead to the decline of mechanical property. The corrosion resistance of Al-Mg-Si alloy is in inverse proportion to the content of Mg and Si associated with the density of the second phase. Corrosion always occurs in second phase or the matrix around them, while the quantity of second phase is in direct proportion to the element content, which means the alloy with higher content of Mg and Si is more susceptible to be corroded.更多还原