3D打印铝合金表面Ce-ZSM-5自愈合膜制备及应力腐蚀开裂防护

Preparation of Ce-ZSM-5 Self-healing Film on 3D Printed Aluminium Alloy Surface and Stress Corrosion Crack Protection

在3D打印铝合金表面制备防腐膜可有效提高金属材料抗应力腐蚀性能。本研究在3D打印铝合金表面制备了Ce-ZSM-5自愈合膜,并结合电化学阻抗谱(EIS)原位解析法和数字图像相关技术(DIC)研究其对应力腐蚀开裂(SCC)的防护作用和相关机理。研究结果表明:与3D打印铝合金相比,含Ce-ZSM-5自愈合膜的3D打印铝合金的裂纹加速扩展时间和断裂时间均延后了0.5 h。对于一般3D打印铝合金,在裂纹萌生时刻,有局部应变集中区域;裂纹加速扩展时刻,应变集中区域逐渐增大且应变幅度增大;在宏观应变集中出现时刻,应变集中幅度继续增大,说明在此区域微裂纹继续加速扩展且开始汇合。对于含自愈合膜的3D打印铝合金,其防护过程是分两个阶段进行:第一阶段,铝合金表面在防腐膜的作用下,侵蚀性离子无法进入,铝合金基体表面无裂纹产生;第二阶段,随应力和应变持续增加,自愈合膜遭到破坏,铝合金表面产生微裂纹,同时储存在ZSM-5中的Ce^(3+)被释放到裂纹处,与腐蚀过程中产生的氢氧根离子反应生成了Ce(OH)_(3)或CeO_(2)沉淀,达到自愈合的效果。

The preparation of corrosion resistant films on the surface of 3D printed aluminum alloys can effectively improve the stress corrosion resistance of metallic materials.In this paper,a Ce-ZSM-5 self-healing film was prepared on the surface of a 3D printed aluminum alloy,and its protective effect and mechanism of the stress corrosion cracking(SCC)were investigated by combining electrochemical impedance spectroscopy(EIS)in-situ analysis method and digital image correlation technique(DIC).The results showed that the crack acceleration extension time and fracture time of the 3D printed aluminum alloy containing Ce-ZSM-5 selfhealing films were delayed by 0.5 h compared to the 3D printed aluminum alloy.For 3D printed aluminum alloys,at the moment of crack initiation,there is a local strain concentration area.At the moment of accelerated crack expansion,the strain concentration area gradually increases and the strain magnitude increases.At the moment of the appearance of macroscopic strain concentration,the strain concentration magnitude continues to increase,indicating that the microcracks continue to accelerate and begin to converge in this area.For the 3D printed aluminum alloy with self-healing films,the protection process is carried out in two stages.In the first stage,the surface of aluminum alloys cannot be accessed by aggressive ions under the action of corrosion protection films,and no cracks are generated on the surface of aluminum alloy substrates.In the second stage,as the stress and strain continue to increase,the self-healing film is damaged and microcracks are generated on the surface of aluminum alloy,while Ce^(3+)stored in ZSM-5 after the destruction of corrosion protection film is released to the cracks and reacts with the hydroxide ions generated in the corrosion process to generate Ce(OH)_(3)or CeO_(2)deposits to achieve the effect of self-healing.