Thermodynamic framework for assessing dissolutive wetting behaviors in metallic systems

Despite its significance in practical applications, until today dissolutive wetting in metallic systems remains poorly understood due to the intricate liquid/solid interactions. In this study, we investigate nine metallic systems encompassing a vast range of thermodynamic behaviors. Our findings reveal three distinct wetting behaviors and identify two key thermodynamic parameters that control solid solution formation and then dissolutive wetting behaviors, namely the solubility of the substrate element in the liquid ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow> <mml:mrow><mml:mi>L</mml:mi></mml:mrow> </mml:msub> </mml:math> ) and the solidification composition range ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow> <mml:mrow><mml:mi>R</mml:mi></mml:mrow> </mml:msub> </mml:math> ). We observe a slow spreading due to the step flow mechanism in systems with a relatively low <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow> <mml:mrow><mml:mi>L</mml:mi></mml:mrow> </mml:msub> </mml:math> and narrow <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow> <mml:mrow><mml:mi>R</mml:mi></mml:mrow> </mml:msub> </mml:math> . For systems with high <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow> <mml:mrow><mml:mi>L</mml:mi></mml:mrow> </mml:msub> </mml:math> , the spreading begins relatively fast and transitions to the step flow mechanism when <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow> <mml:mrow><mml:mi>L</mml:mi></mml:mrow> </mml:msub> </mml:math> is reached. Systems with a large <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow> <mml:mrow><mml:mi>R</mml:mi></mml:mrow> </mml:msub> </mml:math> , conversely, exhibit consistently fast spreading. Density functional theory (DFT) calculations provide deeper insights into the underlying atomistic mechanisms affecting the solid solution formation. Our results offer inspiration for optimizing high-temperature processing techniques, such as welding, coating and high temperature infiltrating.