J. Mater. Sci. Technol. ›› 2016, Vol. 32 ›› Issue (1): 48-53.DOI: 10.1016/j.jmst.2015.10.013

• Orginal Article • Previous Articles     Next Articles

Segregation Behavior and Evolution Mechanism of Iron-Rich Phases in Molten Magnesium Alloys

Yaoxian Zhang, Wencheng Liu, Xiangfa Liu   

  1. Key Laboratory of Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
  • Received:2015-06-19 Revised:2015-08-05 Online:2016-01-19

Abstract: A new method has been proposed to prepare Mg-Al-Si master alloys by utilizing scrap Al-Si-Fe alloys with higher Fe levels, which aims to segregate Fe from Al-Si-Fe alloys by Mg melt. The segregation behaviors, microstructure morphology and evolution mechanism of iron-rich phases in Mg-Al-Si alloy melts were studied, after Al-14Si-4Fe (wt%) alloys were added and dissolved completely. In the Mg-Al-Si alloys, iron has very little solubility and tends to combine with other elements to form intermetallic phases, which grow into a deposition layer due to the higher density. During the cooling and solidifying process of Mg-Al-Si melts, the needle-like Al5SiFe phase in Al-14Si-4Fe alloy evolved into blocky Al5Fe2 and Al0.7Fe3Si0.3 phases. Besides, the Fe levels of the Mg-Al-Si master alloys were reduced to 0.017 wt% from nominal content of 0.164 wt%. Based on the above results, this work carried out a semi-quantitative phase-compositions analysis for the deposition layer by relative intensity ratio (RIR) method, and evolution mechanism of the iron-rich phases had also been discussed. This study has paved a new way to regenerate the scrap Al-Si-Fe alloys, which has a great significance of promoting the recycling of aluminum resources.

Key words: Iron-rich phases, Mg alloy, Segregation behavior, Evolution mechanism, Recycling of scrap Al alloys