Phase control and formation mechanism of Al-Mn(-Fe) intermetallic particles in Mg-Al-based alloys with FeCl₃ addition or melt superheating

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• 作者：Guang Han ; ^{Guang.Han@glasgow.ac.uk" class="auth_mail" title="E-mail the corresponding author} ; Xiangfa Liu ; ^{xfliu@sdu.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Magnesium alloys ; Intermetallics ; τ-Al0.89Mn1.11 ; γ2-Al8Mn5
• 刊名：Acta Materialia
• 出版年：2016
• 出版时间：1 August 2016
• 年：2016
• 卷：114
• 期：Complete
• 页码：54-66
• 全文大小：3464 K

文摘

In this study, we identify the crystal structures and elucidate the formation mechanism of Al–Mn(–Fe) intermetallic particles formed in Mg–Al-based alloys with varied Al contents, FeCl₃ addition or melt superheating. The formed Al–Mn(–Fe) particles were collected through a newly developed particle extraction method for structural, chemical and morphological characterizations. It is found that increasing the Al content from 3 wt% to 9 wt% changes the major Al–Mn phase from τ-Al_0.89Mn_1.11 in AZ31 to γ₂-Al₈Mn₅ in AZ91, and both FeCl₃ addition and melt superheating promote the formation of γ₂-Al₈(Mn,Fe)₅ in AZ31 and AZ63. In addition, through tuning FeCl₃ addition level or melt superheating temperature, different morphologies of the γ₂-Al₈(Mn,Fe)₅ particles are formed in AZ31 and AZ63, including quasi-cubes, octa-pod microstructures and polyhedral particles. This study provides several important approaches to control the crystal structure and morphology of Al–Mn(–Fe) intermetallic particles formed in Mg–Al-based alloys.