(1. 蘭州理工大學(xué) 有色金屬新材料國家重點(diǎn)實(shí)驗(yàn)室培育基地，蘭州 730050；
2. Faculty of Engineering, The University of Auckland, Auckland 1142, New Zealand)
摘 要: 研究AZ91D鎂合金的固溶處理對其微弧氧化成膜的影響。結(jié)果表明：固溶態(tài)基體由于成分分布均勻而能夠迅速成膜并長大，且在相同的微弧化處理時間內(nèi)其膜層厚度始終大于鑄態(tài)基體上的膜層厚度，提高幅度約為40%；隨反應(yīng)時間的延長，膜層厚度逐漸增加，微弧氧化膜表面的噴射空洞和噴射沉積物呈現(xiàn)粗大化趨勢，膜層表面粗糙度也隨之增大；在微弧氧化反應(yīng)初期，固溶態(tài)基體上膜層粗糙度較小；反應(yīng)約100 s后，固溶態(tài)基體膜層的粗糙度逐漸超過鑄態(tài)基體膜層的粗糙度；當(dāng)微弧氧化膜厚度相同時，固溶態(tài)基體上膜層的粗糙度始終小于鑄態(tài)基體膜層的；微弧氧化膜上存在微裂紋，鑄態(tài)基體膜層上的裂紋深而長，呈連續(xù)分布且隨處可見；固溶態(tài)基體膜層上裂紋淺而短，呈單個分布且數(shù)量較少；固溶處理帶來的基體成分的均勻化能降低微弧氧化生成同厚度膜層的能耗。
關(guān)鍵字: AZ91D鎂合金；熱處理；微弧氧化膜
AZ91D magnesium alloy
（1. State Key Laboratory of Advanced Non-ferrous Metal Materials, Lanzhou University of Technology,
Lanzhou 730050, China;
2. Faculty of Engineering, The University of Auckland, Auckland 1142, New Zealand）
Abstract:The effects of solid solution heat treatment on micro-arc oxidation (MAO) coatings on AZ91D magnesium alloys were investigated. The results show that the homogenous element distribution in AZ91D substrate resulted from the solution heat treatment enhances the growth of MAO coatings, and the coatings on the solution-treated samples are about 40% thicker than that on the as-cast samples. With the oxidation process going and the coatings growing, the discharging hole and the ejecting deposition on the coating surface become bigger and coarser, which in turn results in the increase of surface roughness of coatings. At the beginning of the oxidation process, the roughness of the coatings on the solution-treated samples is lower than that on the as-cast samples, while it goes opposite after about 100 s later. However, the coating surface on the samples treated by solid solution is always rougher than that on the as-cast samples if based on the same coating thickness. A few cracks featured with shallow and short morphology are observed on the coatings of the solution treated samples, but more cracks with deep and long features occur in the as-cast samples. Also the even element distribution in the substrates due to the solution treatment contributes to the energy saving if producing MAO coatings with the same thickness.
Key words: AZ91D magnesium alloy; heat treatment; microarc oxidation; coating
