High-Throughput Nanoindentation Mapping of Additively Manufactured T91 Steel

Moujhuri Sau, Eric D. Hintsala, Youxing Chen, Douglas D. Stauffer, Stuart A. Maloy, Benjamin P. Eftink, Thomas J. Lienert, Nathan A. Mara

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


This work aims to adapt nanoindentation mapping combined with a k-means algorithm as a high-throughput technique to study the nano-scale spatial changes in mechanical properties for a heterogeneous material. This technique can also classify the individual data points based on their properties. Hundreds to thousands of indents were performed on additively manufactured T91 at room temperature, 300°C, 400°C, and 500°C across a square area with a side length of 120 μm to 400 μm. From this data, the hardness and reduced modulus at each point could be calculated and mapped. Using k-means clustering, we were able to arrange the data into three or four clusters corresponding roughly to the ferritic and martensitic phases as well as one or two intermediate clusters sampling both the phases. The hardness of these two phases appears to be quite stable as a function of temperature. Nanoindentation mapping and the k-means algorithm can therefore be used to rapidly assess the feasibility of heterogeneous materials under extreme conditions, such as nuclear reactor steels.

Original languageEnglish (US)
StateAccepted/In press - 2022

Bibliographical note

Funding Information:
The custom nanoindentation system at Bruker’s Hysitron was built under DOE SBIR In Operando SPM: Variable Pressure and Temperature, under DE-SC0013218. This work was supported by the Department of Energy, Nuclear Engineering University Programs grant NE-000008888. Support from Bruker NANO is also gratefully acknowledged. EDH and DDS are supported by Bruker. Work was performed in part at Los Alamos National Laboratory. Los Alamos National Laboratory is an affirmative action/equal opportunity employer, and is operated by Triad National Security, LLC for the National Nuclear Security Administration of U.S. Department of Energy under contract 89233218CNA000001

Publisher Copyright:
© 2022, The Minerals, Metals & Materials Society.


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