(1. 中南大學 材料科學與工程學院，長沙 410083；
2. 廣東和勝工業(yè)鋁材股份有限公司，中山 528463)
摘 要: 采用晶間腐蝕實驗結合掃描和透射電鏡分析，研究淬火速率對汽車用新型高強韌鋁合金晶間腐蝕的影響。結果表明：淬火速率從960 ℃/s降低至1.8 ℃/s，晶界淬火析出相的長度及無沉淀析出帶PFZ寬度分別從24.3 nm和23.7 nm增加至94.5 nm和97.8 nm，晶間腐蝕等級從3級增加至4級，最大腐蝕深度和平均腐蝕深度從71.6 μm和60.3 μm分別增加至174.2 μm和157.9 μm。隨著淬火速率的減小，晶界析出相的粒徑增加，晶界析出相的相間距增加，晶界PFZ寬度也相應增大，晶界析出相的Zn含量增加最快，Mg含量的增加次之，Cu含量的增加最慢，從而導致晶間腐蝕深度增加。
關鍵字: 鋁合金；淬火速率；無沉淀析出帶；晶間腐蝕
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Guangdong Hoshion Industrial Aluminium Co., Ltd., Zhongshan 528463, China）
Abstract:The influence of quenching rate on intergranular corrosion of novel high strength and toughness automobile aluminum alloys was investigated by intergranular corrosion experiments, scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results show that, when the quenching rate decreases from 960 ℃/s to 1.8 ℃/s, the size of the precipitates on the grain boundary and the width of precipitate free zone (PFZ) increase from 24.3 nm to 94.5 nm and 23.7 nm to 97.8 nm, respectively. In addition, the corrosion grade increases from 3 grade to 4 grade. The maximum corrosion depth and average corrosion depth increase from 71.6 μm to 174.2 μm and 60.3 μm to157.9 μm, respectively. The element contents of grain boundary precipitates are also altered during the quenching rate changing. That is to say, the increasing of Zn content is the fastest, followed by Mg content, and the increase of Cu content is the slowest, which results in the deepening of intergranular corrosion depth.
Key words: aluminum alloy; quenching rate; precipitate free zone; intergranular corrosion
