碳纤维环氧复合材料对铝合金应力腐蚀性能的影响

Influence of graphite epoxy composite materials on the stress corrosion cracking of aluminum alloys

研究了碳纤维环氧复合材料与LY12CZ,LC4CS铝合金相互偶接时,在3.5%NaCl溶液中的电偶腐蚀行为,以及所产生的电偶腐蚀对铝合金应力腐蚀性能的影响。测量了复合材料与铝合金在3.5%NaCl溶液中的电偶腐蚀电流及铝合金的腐蚀失重值,应用慢应变速率应力腐蚀(SSRT)、预制疲劳裂纹的双悬臂(DCB)试样应力腐蚀研究方法,研究在腐蚀介质和碳纤维环氧复合材料共同作用下,由于电偶腐蚀的存在,对铝合金应力腐蚀性能的影响。试验结果表明:碳纤维环氧复合材料增加LY12CZ铝合金的应力腐蚀敏感性,缩短断裂时间,而对LC4CS双悬臂(DCB)试样应力腐蚀的研究结果表明,电偶腐蚀对LC4CS铝合金KISCC值影响不大,对(da/dt) 稍有影响,但不十分明显。同时对电偶腐蚀影响铝合金的应力腐蚀机制和行为进行了一定的讨论。

Galvanic corrosion induced by graphite epoxy composite materials (GECM) coupled to LY12CZ and LC4CS aluminum alloys in neutral and air-saturated aqueous 3.5% NaCl solution has been investigated. The galvanic corrosion behavior was studied by continuous measurement of the galvanic current and by weight loss measurements. The slow strain rate test (SSRT) and double cantilever beam (DCB) specimens were used to evaluate the SCC of the aluminum alloys. The SSRT results showed that the galvanic corrosion between GECM and LY12CZ aluminum alloy increased the LY12CZ stress corrosion crack growth rate, but reduced the crack time. In DCB stress corrosion test, the KISCC of LC4CS aluminum alloy did not change greatly in relation to the galvanic corrosion, but the date of (da/dt)I was increased a little by GECM. The mechanism and performance responsible for SCC of aluminum alloy affected by the galvanic corrosion were also discussed.