Interrelation between thermodynamics and elasticity in solid state precipitation in austenitic materials
This project wass dedicated to the understanding of coherent precipitates in shape memory alloys, and a more detailed description of the findings is given below. This project was completed at the end of 2010.
We have simulated small model systems of one, two and four Ni4Ti3 particles by the multi-phase field method. Simulation results provide a good description of the precipitation morphology as described in experimental work. In particular we found that external stress changes the thickness of the lenticular precipitates. Furthermore, two closely spaced Ni4Ti3 precipitates, which are coupled by diffusive and mechanical interactions, can promote the nucleation of a third particle. This rationalizes the experimentally observed autocatalytic nucleation and precipitation sequences.
This project was carried out in collaboration between Wei Guo, Ingo Steinbach, Christoph Somsen (LWW RUB) and Gunther Eggeler.