Application of computational thermodynamics to Fe/Ni, Fe-3%Si/Ni and 316L/Ni systems produced by powder metallurgy

ABSTRACT

The commercial simulation software packages, Thermo-Calc and DICTRA, are widely used to predict phase formation and diffusion in materials prepared by traditional metallurgical processes. The goal of this work was to clarify whether the software can also be applied to materials produced by powder metallurgy techniques. For this purpose, diffusion couples of the material combinations Fe/Ni, Fe-3%Si/Ni and 316L/Ni were prepared by two techniques: co-pressing of powders followed by co-sintering and joining of two sintered parts followed by annealing. Thermo-Calc and DICTRA were used to predict interface formation and phase transformations during heat treatments. Scanning electron micrography and energy-dispersive X-ray spectrometry showed the formation of interdiffusion interfaces. The diffusion rate was higher in co-sintered couples, resulting in broader interdiffusion zones than those predicted by simulations, but the annealed couples exhibited interdiffusion profiles similar to those predicted by DICTRA simulations. In general, simulations and experimental results showed the same tendencies.

KEYWORDS:

• Thermo-Calc
• DICTRA
• phase diagram
• simulation
• CALPHAD
• co-sintering
• diffusion
• annealing

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Guilherme Oliveira Neves received his M.Sc. in Materials Science and Engineering in 2016 from Federal University of Santa Catarina, Brazil. He is currently pursuing Ph.D. in Materials Science and Engineering from the Federal University of Santa Catarina, Brazil. His main research activity is devoted to powder metallurgy, computation thermodynamics, and solid lubrication.

Heitor Goebel Tirollo is currently an undergraduate student of Mechanical Engineering from Federal University of Santa Catarina, Brazil.

Sônia Maria Hickel Probst received her Ph.D. in Applied Chemistry in 1989 from University of Poitiers, France. She is currently an associate professor in the Federal University of Santa Catarina, Brazil. Her main research activity is devoted to thermodynamics, chemical kinetics, and corrosion.

Cristiano Binder received his Ph.D. in Materials Science and Engineering in 2009 from Federal University of Santa Catarina, Brazil. He is currently an assistant professor in the Federal University of Santa Catarina, Brazil. His main research activity is devoted to powder metallurgy, plasma processing and surface engineering.

Aloísio Nelmo Klein received his Ph.D. in Engineering in 1983 from Technische Universität Karlsruhe, Germany. He is currently a full professor in the Federal University of Santa Catarina, Brazil and has been the coordinator of the Materials Laboratory (Labmat/UFSC) since 1984. His main research activity is devoted to powder metallurgy, plasma processing, and surface engineering.

ORCID

G. O. Neves http://orcid.org/0000-0001-9733-8582

S. M. H. Probst http://orcid.org/0000-0001-8691-5014

Additional information

Funding

The authors acknowledge the following Brazilian agencies for funding this research: CNPq, Capes, BNDES and FAPESC, as well as Whirlpool/Embraco, and the LCME-UFSC for the technical support.