Dihedral angle measurement in microgravity liquid phase sintered microstructures

摘要

Liquid phase sintered materials are characterized by a connected microstructure composed of contacting grains in a solidified matrix phase. Characterizations on the sintered microstructure are typically performed by two-dimensional cross sections. A new dihedral angle model based totally on the geometry of the spherical solid grains without any further assumptions is presented in this paper to determine the dihedral angles measured in two-dimensional sections vs. the dihedral angles in three dimensions. The result shows that the average dihedral angle measured on sections is 14/15 the dihedral angle in three dimensions. The expected frequencies of the simulation are favorably compared with the experimental results obtained from microgravity liquid phase sintered Fe-Cu alloys with four different solid volume fractions (50, 60, 70, 80 vol% Fe balanced with Cu) and six different sintering times (10, 20, 30, 40, 60 and 330 minutes) when a 3-D dihedral angle with a standard deviation of 10°, in our case, 40° ± 10°, was employed in the model. The goodness of fit of the theoretical 2-D results with the experimental data was determined by chi-squared test. The fit of the data is good since all the computed values of χ2 are smaller than the critical value.