A Combined Experimental and First-Principles Based Assessment of Finite-Temperature Thermodynamic Properties of Intermetallic Al3Sc

Materials

Vladimir Esin¹  Blazej Grabowski²  SergiyV. Divinski³  Yulia Neitzel³  Gerhard Wilde³  Bengü Tas³  Biswanath Dutta⁴  Ankit Gupta⁴  Jörg Neugebauer⁴  Tilmann Hickel⁴  Dominique Korbmacher⁴ 

[1] Centre des Matériaux (UMR CNRS 7633), MINES ParisTech, PSL University, 91003 Evry, France;Institute for Materials Science, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany;Institute of Materials Physics, University of Münster, 48149 Münster, Germany;Max-Planck-Institut für Eisenforschung GmbH, D-40237 Düsseldorf, Germany;

关键词: ab initio;    Al-Sc alloys;    heat capacity;    coefficient of thermal expansion;    precipitation;   

DOI  :  10.3390/ma14081837

来源: DOAJ

【 摘 要 】

We present a first-principles assessment of the finite-temperature thermodynamic properties of the intermetallic Al${}_3$Sc phase including the complete spectrum of excitations and compare the theoretical findings with our dilatometric and calorimetric measurements. While significant electronic contributions to the heat capacity and thermal expansion are observed near the melting temperature, anharmonic contributions, and electron–phonon coupling effects are found to be relatively small. On the one hand, these accurate methods are used to demonstrate shortcomings of empirical predictions of phase stabilities such as the Neumann–Kopp rule. On the other hand, their combination with elasticity theory was found to provide an upper limit for the size of Al${}_3$Sc nanoprecipitates needed to maintain coherency with the host matrix. The chemo-mechanical coupling being responsible for the coherency loss of strengthening precipitates is revealed by a combination of state-of-the-art simulations and dedicated experiments. These findings can be exploited to fine-tune the microstructure of Al-Sc-based alloys to approach optimum mechanical properties.

【 授权许可】

Unknown