采用金相检验、扫描电镜分析以及透射电镜测试等方法研究5083铝合金的耐晶间腐蚀性能,并探讨5083铝合金试样上“白色亮条”对铝合金性能的影响及其形成原因。结果表明:5083铝合金试样发生晶间腐蚀后,表面的“白色亮条”使其耐晶间腐蚀性能更好;受晶粒度的影响,同一批次铝合金试样的腐蚀速率有差异,试样上拉长纤维状晶粒的尺寸更大,晶界处析出物相对较少,其耐晶间腐蚀性能更好;由于Mg元素更易在5083铝合金试样两侧发生偏析,因此试样上的晶间腐蚀裂纹呈中间浅、两侧深的趋势,这也导致腐蚀速率较小试样的晶间腐蚀裂纹较浅,试样中部晶间腐蚀裂纹最深;在晶粒度尺寸较大与Mg元素向试样两侧偏析的联合作用下,5083铝合金试样上出现“白色亮条”,这是耐晶间腐蚀性能良好的标志。

The intergranular corrosion resistance properties of 5083 aluminum alloy were studied by metallographic examination, scanning electron microscopy and transmission electron microscopy, and the effect of ‘white bright stripe' on the properties of 5083 aluminum alloy and its formation reasons were discussed. The results show that the ‘white bright stripe' on the surface of 5083 aluminum alloy specimen after intergranular corrosion made its intergranular corrosion resistance better. Affected by the grain size, the corrosion rate of the same batch of aluminum alloy samples was different. The elongated fibrous grains on the sample were larger in size, and the precipitates at the grain boundary were relatively less, so the intergranular corrosion resistance was better. Because the Mg element was more likely to segregate on both sides of the 5083 aluminum alloy sample, the intergranular corrosion cracks on the sample tended to be shallow in the middle and deep on both sides, which also led to the shallow intergranular corrosion cracks of the sample with smaller corrosion rate. The intergranular corrosion cracks in the middle of the sample was the deepest.Under the combined effect of larger grain size and Mg element segregation to both sides of the sample, ‘white bright stripe' appeared on the 5083 aluminum alloy sample, which was a sign of good intergranular corrosion resistance.