CAJ | 학술논문

研究Al-Mg-Si合金晶界组成相(Al-Mg2Si及Al-Mg2Si-Si)间的电化学行为和动态电化学耦合行为,提出Al-Mg-Si合金的晶间腐蚀机理.研究表明,晶界Si的电位比其边缘Al基体的正,在整个腐蚀过程中作为阴极导致其边缘Al基体的阳极溶解；晶界Mg2Si的电位比其边缘Al基体的负,在腐蚀初期作为阳极发生阳极溶解,然而由于Mg2Si中活性较高的元素Mg的优先溶解,不活泼元素Si的富集,致使Mg2Si电位正移,甚至与其边缘Al基体发生极性转换,导致其边缘Al基体的阳极溶解.当n(Mg)/n(Si)＜ 1.73时,随着腐蚀的进行,合金晶界同时会有Mg2Si析出相和Si粒子,腐蚀首先萌生于Mg2Si相和Si边缘的无沉淀带,而后,Si粒子一方面导致其边缘无沉淀带严重的阳极溶解,另一方面加速Mg2Si和晶界无沉淀带的极性转换,从而促使腐蚀沿晶界Si粒子及Mg2Si粒子边缘向无沉淀带发展.
연구Al-Mg-Si합금정계조성상(Al-Mg2Si급Al-Mg2Si-Si)간적전화학행위화동태전화학우합행위,제출Al-Mg-Si합금적정간부식궤리.연구표명,정계Si적전위비기변연Al기체적정,재정개부식과정중작위음겁도치기변연Al기체적양겁용해；정계Mg2Si적전위비기변연Al기체적부,재부식초기작위양겁발생양겁용해,연이유우Mg2Si중활성교고적원소Mg적우선용해,불활발원소Si적부집,치사Mg2Si전위정이,심지여기변연Al기체발생겁성전환,도치기변연Al기체적양겁용해.당n(Mg)/n(Si)＜ 1.73시,수착부식적진행,합금정계동시회유Mg2Si석출상화Si입자,부식수선맹생우Mg2Si상화Si변연적무침정대,이후,Si입자일방면도치기변연무침정대엄중적양겁용해,령일방면가속Mg2Si화정계무침정대적겁성전환,종이촉사부식연정계Si입자급Mg2Si입자변연향무침정대발전.
The electrochemical behaviors and coupling behaviors of the Mg2Si and Si phases with a(Al) were investigated,the corrosion morphologies of Al alloys containing Mg2Si and Si particles were observed,and the corrosion mechanism associated with them in Al-Mg-Si alloys was advanced.The results show that Si particle is always cathodic to the alloy base,Mg2Si is anodic to the alloy base and corrosion occurs on its surface at the beginning.However,during its corrosion process,the preferential dissolution of Mg and the enrichment of Si make Mg2Si transform to cathode from anode,leading to the anodic dissolution and corrosion of the alloy base at its adjacent periphery at a later stage.As the mole ratio of Mg to Si in an Al-Mg-Si alloy is less than 1.73,it contains Mg2Si and Si particles simultaneously in the grain boundary area,and corrosion initiates on the Mg2Si surface and the precipitate-free zone (PFZ) at the adjacent periphery of Si particle.As corrosion time is extended,Si particle leads to severe anodic dissolution and corrosion of the PFZ at its adjacent periphery,expedites the polarity transformation between Mg2Si and the PFZ and accelerates the corrosion of PFZ at the adjacent periphery of Mg2Si particle.