预变形量对2519铝合金抗晶间腐蚀性能的影响

采用硬度测试、扫描电镜与透射电镜研究时效前冷轧预变形量对2519铝合金晶界无沉淀带(PFZ)及第二相大小、分布和抗晶间腐蚀性能的影响。结果表明:经冷轧预变形后,晶间析出相细化并弥散分布,导致各变形量样品的时效硬度均提高,同时使合金到达峰值的时效时间缩短;且随着预变形量的增加,合金晶间腐蚀性能由4级降至0级,抗晶间腐蚀能力增强。这是由于晶界无沉淀带变窄,同时在晶界析出的平衡相由链条状分布逐渐变为不连续分布,使连续网状的腐蚀通道转变为断续的腐蚀点,进而提高了2519合金的抗晶间腐蚀性能。

Effect of degree of predeformation on corrosion resistance of 2519 aluminum alloy

By hardness tests,scanning electron microscopy(SEM) and transmission electron microscopy(TEM),the influence of predeformation reduction before aging on the size and distribution of precipitate phases and inter-(granular) corrosion resistance of 2519 alloy was determined.The results show that the precipitate in grains is fined(after) predeformation reduction.The peak-age hardness of samples is correspondingly improved,and the time for peak-aged is shortened.With the increase of the predeformation reduction,the rate of intergranular corrosion(IGC) of 2519 aluminum alloys decreases from 4 to 0,and the IGC resistance is improved.Along grain boundaries,the precipitation free zones(PFZ) is narrow and the distribution of those precipitates changes from continuous chains to non-continuous ones.Then,the discrete corrosion pits form instead of continuous pathway,which results in higher IGC resistance.