The behaviour of entrainment defects formed in commercial purity Mg alloy cast under a cover gas of SF6

4th International Conference on Advances in Solidification Processes

材料科学;物理学

Li, T.^1 ; Griffiths, W.D.^1

School of Metallurgy and Material, College of Engineering and Physical Science, University of Birmingham, Birmingham

B15 2TT, United Kingdom^1

关键词: Commercial purity;    Complicated structures;    Electron microscopy (SEM);    Entrainment defects;    Fracture surfaces;    Melt surfaces;    Surface films;    Surface turbulence;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/117/1/012065/pdf
DOI  :  10.1088/1757-899X/117/1/012065

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

In the casting of light alloys, the oxidised film on the melt surface can be folded due to surface turbulence, thus forming entrainment defects that have a significant negative effect on the mechanical properties of castings. Previous researchers reported that the surface film of Mg alloys formed in an atmosphere containing SF6had a complicated structure composed of MgO and MgF2. The work reported here aims to investigate the behaviour of entrainment defects formed in magnesium alloys protected by SF6-containing atmospheres. Tensile test bars of commercial purity Mg were cast in an unsealed environment under a cover gas of pure SF6. 34Scanning electron microscopy (SEM) of the fracture surface of the test bars indicated entrainment defects that consisted of symmetrical films containing MgO, but also sulphur and fluorine. The results of these examinations of the symmetrical films were used to infer the potential formation and development of entrainment defects in commercial purity Mg alloy.