CAJ | 학술논문

铝合金中经常会引入一些第二相来改善其性能，第二相由于和铝基体的电位差不同，将会对铝合金的局部腐蚀产生重大的影响。为了揭示铝合金腐蚀的物理本质，本文利用基于密度泛函理论第一性原理的计算方法，详细计算了铝合金中一些主要第二相(Al2Cu、Al3Ti和Al7Cu2Fe)的多种晶面的电子功函数，分析了电子从各个晶面逸出的难易，求得了第二相与Al基体的本征电势差。我们发现不同的晶面暴露在合金最外层，会显著地影响本征电势差；即便是同一晶面，暴露在最外层的原子种类和构型不同，对腐蚀的影响也不一样。从电子的层面解释了电偶腐蚀发生的原因。
려합금중경상회인입일사제이상래개선기성능，제이상유우화려기체적전위차불동，장회대려합금적국부부식산생중대적영향。위료게시려합금부식적물리본질，본문이용기우밀도범함이론제일성원리적계산방법，상세계산료려합금중일사주요제이상(Al2Cu、Al3Ti화Al7Cu2Fe)적다충정면적전자공함수，분석료전자종각개정면일출적난역，구득료제이상여Al기체적본정전세차。아문발현불동적정면폭로재합금최외층，회현저지영향본정전세차；즉편시동일정면，폭로재최외층적원자충류화구형불동，대부식적영향야불일양。종전자적층면해석료전우부식발생적원인。
Al al oys contain some secondary phases to improve their properties. These secondary phases have different potentials to the Al matrix, which greatly affect the localized corrosion of Al al oys. In order to reveal the physical nature of Al al oy corrosion, we use the first-principles method based upon density functional theory to calculate the work function of the main secondary phases (Al2Cu, Al3Ti, and Al7Cu2Fe). The difficulty of electrons escaping from various crystal planes was analyzed, and the potential difference between the secondary phases and Al matrix was obtained. We find that different crystal planes exposed to the outmost layer significantly impacted on the potential difference. Different atomic types at the outmost layer play different roles in Al al oy corrosion, even for the same crystal surface. The causes of galvanic corrosion were thus revealed.