(河北工程大學(xué)裝備制造學(xué)院，邯鄲 056038)
摘 要: 通過晶間腐蝕、剝落腐蝕、電化學(xué)和透射電鏡等方法研究熱處理制度對Al-Cu-Mg-Ag耐熱鋁合金組織與抗腐蝕性能的影響。結(jié)果表明：隨著時效時間的延長，合金晶內(nèi)和晶界析出相逐漸長大，晶界析出相由連續(xù)分布轉(zhuǎn)變?yōu)椴贿B續(xù)分布，無沉淀析出帶(PFZ)逐漸變寬，合金的抗晶界腐蝕性能和抗剝落腐蝕性能逐漸降低。基體腐蝕電位φmatrix、PFZ腐蝕電位φPFZ和晶界析出相腐蝕電位φθ在晶間腐蝕液和剝落腐蝕液中符合φmatrix＞φθ＞φPFZ。具有最低腐蝕電位的PFZ決定了合金的抗腐蝕性能。隨著時效時間的延長，晶界析出相的粗化使得PFZ變寬，Cu原子減少，電位負移，PFZ與基體的電位差變大，腐蝕通道變寬，合金的耐蝕性降低。不同時效狀態(tài)的Al-Cu-Mg-Ag耐熱鋁合金的抗腐蝕能力由強至弱的順序為：欠時效的，峰時效的，過時效的。
關(guān)鍵字: Al-Cu-Mg-Ag；耐熱鋁合金；晶間腐蝕；剝落腐蝕；無沉淀析出帶
（College of Equipment Manufacture, Hebei University of Engineering, Handan 056038, China）
Abstract: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 matrix φmatrix, precipitations on the grain boundaries φθ and the PFZ tested φPFZ both in the intergranular corrosion solution and exfoliation corrosion solution satisfy φmatrix＞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.
Key words: Al-Cu-Mg-Ag; heat-resistant alloy; intergranular corrosion; exfoliation corrosion; precipitation free zone
