Diffusion Module (DICTRA) and TCNI8 Used in Assessment of Additive Manufacturing

DICTRA used in Additive manufacturing assessment

A new publication in the May issue of Acta Materialia uses the Diffusion module (DICTRA) with TCNI8, the Ni-based superalloys database, to investigate how additive manufacturing can improve heat treatment processes in the Ni-based superalloy Inconel 625.

The article, Application of finite element, phase-field, and CALPHAD-based methods to additive manufacturing of Ni-based superalloys, uses three numerical simulation methods to test different aspects of additive manufacturing in heat treatment and compares the results against experimental observations. Thermo-Calc’s Diffusion module (DICTRA), along with the Ni-based superalloys database, TCNI8, is used to predict microsegregation during solidification.

Additive manufacturing has shown a lot of promise in materials science over the past few years to improve development processes and bring down costs of development and manufacturing, but, as the paper points out in its introduction, “Finding suitable stress-relieving and homogenizing heat treatments without sacrificing strength is an iterative process”, making it slow and costly, but, as the paper goes on, “numerical modeling can help narrow the search.”

The paper was written by Trevor Kellera, Greta Lindwalla, Supriyo Ghosha, Li Maa, Brandon M. Lanec, Fan Zhangd, Ursula R. Kattnera, Eric A. Lassa, Jarred C. Heigelc, Yaakov Idella, Maureen E. Williamsa, Andrew J. Allend, Jonathan E. Guyera and Lyle E. Levinea.

Abstract

Numerical simulations are used in this work to investigate aspects of microstructure and microsegregation during rapid solidification of a Ni-based superalloy in a laser powder bed fusion additive manufacturing process. Thermal modeling by finite element analysis simulates the laser melt pool, with surface temperatures in agreement with in situ thermographic measurements on Inconel 625. Geometric and thermal features of the simulated melt pools are extracted and used in subsequent mesoscale simulations. Solidification in the melt pool is simulated on two length scales. For the multicomponent alloy Inconel 625, microsegregation between dendrite arms is calculated using the Scheil-Gulliver solidification model and DICTRA software. Phase-field simulations, using Ni–Nb as a binary analogue to Inconel 625, produced microstructures with primary cellular/dendritic arm spacings in agreement with measured spacings in experimentally observed microstructures and a lesser extent of microsegregation than predicted by DICTRA simulations. The composition profiles are used to compare thermodynamic driving forces for nucleation against experimentally observed precipitates identified by electron and X-ray diffraction analyses. Our analysis lists the precipitates that may form from FCC phase of enriched interdendritic compositions and compares these against experimentally observed phases from 1 h heat treatments at two temperatures: stress relief at 1143 K (870° C) or homogenization at 1423 K (1150° C).

 

Thermo-Calc Software Welcomes John Ågren to the Company

Headshot of John Ågren

John Ågren

Thermo-Calc Software are excited to announce that Prof. John Ågren has joined the company as a Senior Scientific Advisor.

Prof. Ågren was one of the original developers of Thermo-Calc in the late 1970s, working with two others, Bo Sundman and Bo Jansson, to write the preliminary code and develop the initial databases as part of their doctoral thesis projects at the Royal Institute of Technology (KTH) in Stockholm, Sweden. The three students were working on separate projects, but each needed access to thermodynamic data, so they set out to create collaborative software to help them complete their research, and by 1981, they had completed the first version of Thermo-Calc. The software was soon licensed to other organisations, and in 1997, the company Thermo-Calc Software AB was founded.

The focus of Prof. Ågren’s doctoral thesis was diffusion reactions, and his contributions to the software became the foundation for the Diffusion module (DICTRA), which was just released in the graphical mode for the first time this year. Today the Diffusion module (DICTRA) is used at more than 500 organisations in 42 countries around the world.

In 1981, Prof. Ågren’s Doctoral thesis, Computer Simulations of Diffusional Reactions in Multicomponent Alloys with Special Applications to Steel, was accepted and he continued his career in academia. After completing a postdoctoral position at Man Labs Inc. in Massachusetts, USA, Prof. Ågren returned to KTH, becoming a professor in the same department where he earned his doctorate.

His illustrious career has spanned nearly 35 years, during which time he has supervised 28 PhD students through to graduation, won several prestigious awards, including the Hume-Rothery Award, was inducted into the Royal Swedish Academy of Engineering Sciences and has published nearly 200 papers.

Though he was never an employee at Thermo-Calc Software AB, Prof. Ågren has remained involved in the company over the years. He helped found the company in 1997 and has been a member of the board of directors since that time, serving as chairman since 2001.

In March of this year a symposium was held in his honour celebrating his many accomplishments in both science and engineering. Thermo-Calc CEO, Anders Engström, gave a presentation highlighting the many contributions Prof. Ågren has made to science and engineering over his lifetime. You can view the complete presentation and learn more about Prof. Ågren’s research: A master of science, engineering and entrepreneurship.

Anders Engström giving a presentation about John Ågren

Anders Engström (left) giving a presentation at the John Ågren Symposium on the many accomplishments throughout Prof. Ågren’s career.

Prof. Ågren brings immeasurable experience and expertise to Thermo-Calc Software, and we are thrilled to welcome him into the company he helped found. We look forward to working together in this new capacity.

 

THERMO-CALC USED AT TOP UNIVERSITIES

The annual QS World University Rankings by Subjects was released in March, and this year, over 70% of the top 100 universities that specialise in Materials Science are Thermo-Calc users. Thermo-Calc Software have long supported universities and we are proud to see that so many of our users are being recognised as top Materials Science Programs.

The annual QS World University Rankings by Subjects, published by British Quacquarelli Symonds every March, ranks universities around the world in 46 subjects, including Materials Science. Rankings are based on academic reputation, employer reputation and research impact. QS also publish a list of the top universities in the world overall every September, which also includes many Thermo-Calc users.  Continue reading

The Diffusion module (DICTRA) Now Available in the Graphical Mode

The Diffusion module (DICTRA), the software program for accurate simulation of diffusion controlled reactions in multicomponent alloy systems, is now available in the graphical mode beginning with Thermo-Calc 2017a, making it easier than ever for users to begin making diffusion simulations.  Continue reading

Educate the Educators: Summer School for Integrated Computational Materials Education

Current and future educators working in undergraduate thermodynamics, kinetics, mechanics of materials and solid-state physics are encouraged to apply for the 6th Summer School for Integrated Computational Materials Education, which will take place at the University of Michigan, Ann Arbor, June 5-16, 2017. Continue reading

Congratulations to QuesTek on Winning Six SBIR/STTR AWARDS

Thermo-Calc Software would like to congratulate QuesTek Innovations, LLC on their recent award of six separate projects from the U.S. Navy and U.S. Army to develop technologies and design new alloys specifically tailored to the meet the unique challenges of Additive Manufacturing (AM). These six awards are just the latest in a long list of such projects awarded to QuesTek spanning nearly two decades and comprising over 90 US government-funded projects, including several others for additive manufacturing.

QuesTek Innovations LLC have become a global leader in Integrated Computational Materials Engineering (ICME) by using their proprietary Materials by Design® methodology to rapidly develop new materials that reduce capital, processing, operating or maintenance costs, or improve environmental protection or competitive supply. Thermo-Calc Software are proud to have partnered with QuesTek Innovations on a number of projects over the years, including, most recently, the co-founding of QuesTek Europe, a joint venture that was established to offer ICME modelling services and novel materials development and design services to the European market.

To learn more about these six projects and the increasing importance of Additive Manufacturing, read the QuesTek press release.

From all of us at Thermo-Calc Software, congratulations to QuesTek Innovations on these latest awards.

In Loving Memory of Dr. Pingfang Shi

Pingfang Shi

It is with deep sadness that we announce the passing of one of our longest and dearest employees Dr. Pingfang Shi, who died yesterday after a hard-fought battle with cancer. As the first employee of Thermo-Calc Software Pingfang guided us through our uncertain early years and shaped this company into the warm, caring place it is today. He will be greatly missed by all of us. Our thoughts are with his family in this difficult time.