Preferential nucleation during polymorphic transformations

Preferential nucleation during polymorphic transformations

Sharma, H. (Argonne National Laboratory)
Sietsma, J. (TU Delft (OLD) MSE-3)
Offerman, S.E. (TU Delft (OLD) MSE-1)

2016

Polymorphism is the ability of a solid material to exist in more than one phase or crystal structure. Polymorphism may occur in metals, alloys, ceramics, minerals, polymers, and pharmaceutical substances. Unresolved are the conditions for preferential nucleation during polymorphic transformations in which structural relationships or special crystallographic orientation relationships (OR’s) form between the nucleus and surrounding matrix grains. We measured in-situ and simultaneously the nucleation rates of grains that have zero, one, two, three and four special OR’s with the surrounding parent grains. These experiments show a trend in which the activation energy for nucleation becomes smaller – and therefore nucleation more probable - with increasing number of special OR’s. These insights contribute to steering the processing of polymorphic materials with tailored properties, since preferential nucleation affects which crystal structure forms, the average grain size and texture of the material, and thereby - to a large extent - the final properties of the material.

Metals and alloys
Pharmaceutics
Solid-state chemistry
Structural geology

http://resolver.tudelft.nl/uuid:e368b072-2e9a-437b-b110-9d526a2d3552

https://doi.org/10.1038/srep30860

2045-2322

Scientific Reports, 6, 1-7

Institutional Repository

journal article

© 2016 H. Sharma, J. Sietsma, S.E. Offerman