AUTHOR=Chandran Anju , Santhosh Archa , Pistidda Claudio , Jerabek Paul , Aydin Roland C. , Cyron Christian J. 

TITLE=Comparative analysis of ternary TiAlNb interatomic potentials: moment tensor vs. deep learning approaches

JOURNAL=Frontiers in Materials

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2024.1466793

DOI=10.3389/fmats.2024.1466793

ISSN=2296-8016

ABSTRACT=<p>Intermetallic titanium aluminides, leveraging the ordered <inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>γ</mml:mi></mml:mrow></mml:math></inline-formula>-TiAl phase, attract increasing attention in aerospace and automotive engineering due to their favorable mechanical properties at high temperatures. Of particular interest are <inline-formula id="inf2"><mml:math id="m2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>γ</mml:mi></mml:mrow></mml:math></inline-formula>-TiAl-based alloys with a Niobium (Nb) concentration of 5–10 at.%. It is a key question how to model such ternary alloys at the atomic scale with molecular dynamics (MD) simulations to better understand (and subsequently optimize) the alloys. Here, we present a comparative analysis of ternary TiAlNb interatomic potentials developed by the moment tensor potential (MTP) and deep potential molecular dynamics (DeePMD) methods specifically for the above mentioned critical Nb concentration range. We introduce a novel dataset (TiAlNb dataset) for potential training that establishes a benchmark for the assessment of TiAlNb potentials. The potentials were evaluated through rigorous error analysis and performance metrics, alongside calculations of material properties such as elastic constants, equilibrium volume, and lattice constant. Additionally, we explore finite temperature properties including specific heat and thermal expansion with both potentials. Mechanical behaviors, such as uniaxial tension and the calculation of generalized stacking fault energy, are analyzed to determine the impact of Nb alloying in TiAl-based alloys. Our results indicate that Nb alloying generally enhances the ductility of TiAl-based alloys at the expense of reduced strength, with the notable exception of simulations using DeePMD for the <inline-formula id="inf3"><mml:math id="m3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>γ</mml:mi></mml:mrow></mml:math></inline-formula>-TiAl phase, where this trend does not apply.</p>