Papers by Keyword: Solidification Path

Abstract: Taking M142 high power density piston alloy as the research object, using thermo Calc thermodynamic calculation. The solidification path of the alloy system is calculated in the composition range of Cu (3.5% - 6.0wt%), Mg (0.5% - 1.2wt%), Si (11% - 14wt%) and Ni (2.1% - 3.0wt%). The microstructure formation laws of Cu, Mg and Ni elements were obtained. And the relationship between residual structure and temperature and composition in different states and stages. Analysis of alloy element pairs δ Phase (Al3CuNi) γ Phase (Al7Cu4Ni) and other main strengthening phases are analyzed and evaluated comprehensively. Based on the calculation of the solidification path of the alloy, the microstructure of the alloy is optimized, especially the multi eutectic and peritectic structure platform. The microstructure content, composition and temperature precipitation space are comprehensively designed and calculated, so as to optimize the process parameters such as the best composition, temperature and pressure of the alloy.

Abstract: This article is to assess the modeling treatment of the growth kinetics (finite or infinite diffusion in liquid and solid phases) during solidification and its influence on the calculation of macrosegregation. A model of diffusion-governed growth kinetic for ternary alloy is developed and used for this assessment. Solidification of a 2D casting (50 x 50 mm²) of a ternary alloy (Fe-0.45 wt.% C-1.06 wt.%Mn) is considered. The result shows that finite diffusion in liquid, important for the initial stage of solidification, plays very important role in the formation of macrosegregation. Moreover, the role of the finite diffusion kinetics in the formation of macrosegregation shows differently in the two extreme cases of solidification structures (columnar or equiaxed).

Abstract: The solidification path of Al-Cu-Si alloys in the Al-rich corner are investigated. The thermodynamic data needed in the calculation are obtained by direct coupling with the CALPHAD software Thermo-Calc. A paralell experimental investigation is conducted to validate the prediction results. The calculated results show that, the sensitivity of the variations in the solidification paths to the cooling rates are depended on the distance of the initial compositions from the binary eutectic troughs or the ternary eutectic point. Reasonable agreements are observed between the predicted amounts of θ-phase and the measured results.

Abstract: The solution redistribution was an important phenomenon during the solidification of multi-component alloys. The different paths of solidification of different component Al-Si-Mg alloys were calculated in this paper. The calculations were coupled with CALPHAD technology. The interaction of solutes would change the solute redistribution coefficients during the solidification especially in the ends of solidification. The solidification paths were calculated by employing the CALPHAD technology and the binary partition coefficients separately. The results show that errors exist under assuming the partition coefficients of solutes as a constant due to the interaction between solutes in ternary alloys. The predicted solidification processes of Al-Si-Mg alloys agree well with the experimental results in this paper.

Abstract: The effect of Fe content on hot tearing of the high-strength Al-Mg-Si alloy was systematically investigated. In this study, a thermodynamic calculation software Thermo-Calc was used to calculate the solidification path under the non-equilibrium condition, and the mechanical properties of this alloy have also been investigated during solidification using an electromagnetic induction heating tensile machine. In order to confirm the calculation results of solidification path, a quenching test also was carried out. By using the Thermo-Calc, the sequence of crystallization, crystallization temperature of formed phases and their crystallized amount were systematically investigated for each alloy in which Fe content was changed. Furthermore, by comparing the fracture surfaces of the tensile testing sample and DC billet, the temperature range of crack initiation of the alloy was examined. Comparing the temperature range of crack initiation with the crystallization phase and its crystallization order, Fe content of high-strength Al-Mg-Si alloy influenced hot tearing significantly owing to the crystallization behavior of α(AlFeMn).