Crystalline-Phase Solidification Analysis Using In Situ Neutron Diffraction

In situ neutron diffraction was utilized to examine the solidification behavior of aluminum and magnesium alloys for further understanding of solidification, hot tearing, and grain refinement. The experiments consisted of melting samples and allowing them to cool while being irradiated by neutrons. During solidification, solid phases enabled diffraction of neutrons. The diffraction profiles were collected at each temperature step and were used to interpret the growth of individual planes and phases. In situ neutron diffraction enabled determination of fraction solid curves for individual planes and phases, which was not possible with traditional thermal analysis and computational techniques. This paper outlines the method of generation of fraction solid curves from neutron diffraction intensity data, including a technique to account for the effects of the Debye-Waller factor. This method was successful in revealing detailed insights into crystalline solidification. It showed promise in quantifying many other phenomena beyond those discussed.