2D Quantitative Characterization of Microstructural Inhomogeneities in the Pressure Die Cast AZ91 Magnesium Alloy

Abstract

Inclusions, shrinkage pores and gas pores are the major processing defects of pressure die cast AZ91 magnesium alloy. These inhomogeneities influence the mechanical properties of the material. Hence, quantitative characterization of size and arrangement of inclusions, shrinkage and gas microporosity is expected to be useful to understand the processing-property-microstructure correlation. In the present work an image analysis procedure has been explained to separately quantify the above inhomogeneities. The important parameters of image processing like montage creation, magnification selection and shrinkage pore separation are explained. The inclusions, shrinkage and gas micropores were separated by the above procedure and size, nearest neighbor distance distributions of these inhomogeneities were obtained in order to characterize the material.

Effect of long term annealing on the microstructure and tensile properties of hpdc AZ91 Mg alloy

“…The values of clustering tendency below 1 indicate clustering, equal to 1; random, equal to 2.15; uniform distributions. The details of montage creation and the quantification procedure of microporosity and ␤ phase are presented elsewhere [11,12,13]. In addition, in situ tensile analysis coupled with SEM was performed to understand the microscopic failure mode of the material.…”

Effect of position on the tensile properties in high-pressure die cast Mg alloy

“…This microstructural frames were used to create the microstructural montage and it was further introduced to image processing to quantify the gas and shrinkage microporosity. The nearest neighbour distance limit is used to separate the gas and shrinkage porosity and the detailed procedure is presented elsewhere [13][14][15][16]. The unetched crosssection was further etched (with a combination of picric acid (6 g), water (10 ml), acetic acid (5 ml) and ethanol (100 ml)) to reveal the ␤ phase.…”

Micro–macro interactions and effect of section thickness of hpdc AZ91 Mg alloy

“…The microstructural area of 1.86 mm 2 was grabbed at 1000× for the quantification of ␤ phase by image processing. The details of montage creation and the quantification procedure of microporosity and ␤ phase are presented elsewhere [13,14]. In addition, in situ tensile analysis coupled with SEM was performed to understand the microscopic failure mode of the material.…”