Competitive crystallization in Al-Sm involving metastable large-unit-cell intermetallic phases: chemical partitioning and crystal genes

21^st International Conference on Advanced Materials & Nanotechnology

September 04-06, 2018 | Zurich, Switzerland

R E Napolitano, F Meng, R T Ott, S H Zhou and W Wang

Iowa State University, USA Ames Laboratory, USA

Posters & Accepted Abstracts: Res. Rev. J Mat. Sci

DOI: 10.4172/2321-6212-C3-021

Abstract

Amorphous alloys of Al-Sm exhibit competitive devitrification behavior upon reheating, involving competition between multiple metastable phases. These include large-unit-cell phases with cubic, hexagonal and tetragonal symmetry, along with more conventional stable and metastable compounds. Phase selection during crystallization is strongly path dependent, owing to effects of non-crystalline ordering and the role of diffusion and chemical partitioning in the morphological dynamics. In this work, devitrification kinetics is investigated and quantified using high energy X-ray diffraction, thermal analysis and electron microscopy. Measurements are related to system thermodynamics in the highly driven regime highlighting principles of selection. Growth mechanisms are investigated in detail, with particular attention to chemical partitioning associated with the initial crystallization front. Implications with respect to other Al-RE (rare-earth) systems are also discussed.

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