Effect of hydrogen content on the double oxide film defects and properties of aluminium castings: A review

Entrapped double oxide films are known to be the most detrimental defects in cast aluminium alloys. In addition, hydrogen dissolved in the aluminium melt was suggested to pass into the defects to expand them and cause hydrogen porosity. This paper presents a comprehensive review of the concept of double oxide film defects with an emphasize on the influence of the dissolved hydrogen on the morphology of the defects in aluminium melts and in turn how such effect could govern the tensile and fatigue properties of the castings. This will give a better understanding of factors influencing the properties of light metal alloy castings which would lead to the development of improved practices by which healthier castings with reliable and more reproducible properties are obtained