Analysis of Microsegregation in Al-Si-Cu Ternary Alloys: Interdependence of Solute Composition at the Solubility Limit during Non-Equilibrium Solidification

Abstract

Virtually all metals used industrially undergo a solidification process during their production. Depending on the material and its manufacturing process, its physical/mechanical properties are affected to a greater or lesser extent by the microstructure and microsegregation obtained during the phase change. Aluminum casting alloys are good examples of products where this microstructure is vital for obtaining the desired properties. A sequence of experiments to analyze the upward vertical unidirectional solidification with transient heat transfer conditions in Al-Si-Cu ternary alloys was developed in the present work. The experimental results obtained were compared with classical microsegregation models. Discrepancies related to their use for ternary alloys were raised. Since the calculated results by these models do not take into account the influence of one alloying element on the solubility of the other element, disparities were founded between experimental and numerical results. A microsegregation model was proposed based on the solubility limits of the Si in the alloy as a function of the Cu concentration present in the liquid. The model, combined with the concepts of classical microsegregation theory, allows a realistic description of the microsegregation phenomenon. The model showed an excellent agreement between microsegregation profiles of solute experimentally measured and calculated.

Influência do Cu, Si e Ni e parâmetros térmicos de solidificação sobre as propriedades mecânicas e microestrutura em ligas hipoeutéticas à base de Al

“…O sistema de resfriamento à água do molde contribui para a alta velocidade de solidificação nas regiões próximas à base resfriada. Comportamento convergente com resultados de trabalhos anteriores (Sales et al, 2018;Baptista et al, 2020;Barros et al, 2024a). (tSL= 3,19P 0.87 e R 2 = 0.99) e Al-5%Ni (tSL= 0,3157P 0.9227 e R 2 = 0.85).…”

“…É o mais importante dos metais não ferrosos e está entre os mais consumidos atualmente. O rápido e notável crescimento da sua utilização deve-se à sua versatilidade e propriedades físicas, especialmente sua baixa densidade em comparação com outros metais de grande consumo, resistência à corrosão, baixo ponto de fusão e alta condutividade elétrica (Baptista et al, 2020). Devido a essas propriedades, as ligas de alumínio são frequentemente uma escolha preferida nas indústrias aeronáutica e aeroespacial, bem como para diversas aplicações de engenharia (Rodrigues et al, 2023;Xiao et al, 2023;Yong-fei et al, 2023;Garchani et al, 2023;Garção et al, 2023).…”