Quantitative characterization of spatial arrangement of shrinkage and gas (air) pores in cast magnesium alloys

Pressure die-cast magnesium (Mg) alloys contain both shrinkage and gas (air) microporosity. Characterization of shrinkage and (gas) air microporosity is essential for understanding microstructure–properties correlations in these alloys. In this contribution, a recently reported digital image analysis (DIA) technique has been further developed to separately quantify and characterize the attributes of shrinkage and air microporosity in AM series of cast Mg alloys. The image analysis procedure is utilized to measure the nearest-neighbor distributions of the shrinkage and gas (air) pores, and to quantify the clustering tendency of the pores. A new affinity parameter is defined to characterize the affinity of gas (air) pores to shrinkage pores and vice versa. The affinity parameters are computed from the same image analysis data.