摘要
通过晶间腐蚀、剥落腐蚀、电化学和透射电镜等方法研究热处理制度对Al-Cu-Mg-Ag耐热铝合金组织与抗腐蚀性能的影响。结果表明:随着时效时间的延长,合金晶内和晶界析出相逐渐长大,晶界析出相由连续分布转变为不连续分布,无沉淀析出带(PFZ)逐渐变宽,合金的抗晶界腐蚀性能和抗剥落腐蚀性能逐渐降低。基体腐蚀电位φmatrix、PFZ腐蚀电位φPFZ和晶界析出相腐蚀电位φθ在晶间腐蚀液和剥落腐蚀液中符合φmatrix>φθ>φPFZ。具有最低腐蚀电位的PFZ决定了合金的抗腐蚀性能。随着时效时间的延长,晶界析出相的粗化使得PFZ变宽,Cu原子减少,电位负移,PFZ与基体的电位差变大,腐蚀通道变宽,合金的耐蚀性降低。不同时效状态的Al-Cu-Mg-Ag耐热铝合金的抗腐蚀能力由强至弱的顺序为:欠时效的,峰时效的,过时效的。
The effects of the aging treatment on the microstructure and the corrosion resistance of Al-Cu-Mg-Ag heat-resistant aluminium alloy were studied by intergranular corrosion, exfoliation corrosion, electrochemical analysis and transmission electron microcopy. The results show that with increasing aging time, the precipitations both in the grains and on the grain boundaries grow, the distribution of the precipitations on the grain boundaries transforms from continuous to discontinuous, and the precipitation free zone (PFZ) widens, the intergranular corrosion resistance and the exfoliation corrosion resistance decrease. The self-corrosion potential of the matrixφmatrix, precipitations on the grain boundariesφθ and the PFZ testedφPFZ both in the intergranular corrosion solution and exfoliation corrosion solution satisfyφmatrix>φθ>φPFZ. The corrosion resistance of Al-Cu-Mg-Ag alloy is determined by PFZ with the lowest self-corrosion potential. With increasing aging time, the PFZ widens with less Cu solution atoms, leading to lower potential and wider corrosion passageway. This results in the larger potential difference between the matrix and the PFZ, and the corrosion resistance correspondingly decreases. The corrosion resistance of Al-Cu-Mg-Ag heat-resistant aluminium alloy changing from high to low are as follows: under-aged, peak-aged, over-aged.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2015年第11期3033-3039,共7页
The Chinese Journal of Nonferrous Metals
基金
河北省自然科学基金资助项目(E2013402056)
河北省高等学校科学技术研究项目(QN2014002)
邯郸市科学技术研究与发展计划项目(1321110085-4)
