Microstructure evolution of aluminum powder during sintering

Real-time and non-destructive observation of sintering was realized by synchrotron radiation X-ray computed tomography (SR-CT) technique. The projection images of the sample were captured by an X-ray CCD camera at different sintering times. Two-dimensional and three-dimensional reconstructed images were obtained by treating the projection images with filtered back projection algorithm and digital image analysis method. Several sintering phenomena such as grain contact, sintering neck growth and pore spheroidization were observed from the reconstructed images. The porosity-sintering time and porosity-time logarithm curves were obtained from reconstructed images of the sample at different sintering times. Three sintering stages and linear relationship between porosity and time logarithm in the middle stage of sintering were clearly observed from the curves. The experiment results are in concordance with the traditional sintering theory.