Porosity

Porosity is the presence of voids or holes in what should be a solid metal structure. Porosity can be caused by gas bubbles, lack of sufficient liquid or metal to fill the joint or mold, etc. Some porosity is present in even the best and highest quality of castings. However, large amounts of porosity decrease the amount of metal present to resist stress. Porosity in a metal can also provide and act as stress risers (precursors to failure).