Prediction of the solidification path of Al-4.37Cu-27.02Mg ternary eutectic alloy with a unified microsegregation model coupled with Thermo-Calc

• Published in: International journal of materials research Vol. 104; no. 3; pp. 244 - 254
• Main Authors: Yan, Erhu, Li, Xinzhong, Su, Yanqing, Liu, Dongmei, Xu, Daming, Guo, Jingjie, Fu, Hengzhi
• Format: Journal Article
• Language: English
• Published: Munich De Gruyter 14.03.2013; Hanser
• Subjects: Aluminum base alloys; Al–Cu-Mg eutectic alloy; Applied sciences; Cooling rate; Diffusion coefficient; Eutectic alloys; Eutectics; Exact sciences and technology; Joining; Mathematical models; Metals. Metallurgy; Microsegregation model; Solidification; Solidification path; Thermo-Calc; Volume fraction; Aluminium base alloys; Eutectic alloy; Ternary alloy; Al-Cu-Mg eutectic alloy; Microsegregation model; Prediction; Modeling; Thermo-Calc; Solidification; Solidification path; Eutectic; Magnesium alloy; Microstructure; Copper alloy; Microsegregation
• ISSN: 1862-5282; 2195-8556
• DOI: 10.3139/146.110854

An extended unified microsegregation model with solid back diffusion effects and five different dendrite morphologies was used to investigate the solidification path of Al-4.37Cu-27.02Mg (wt.%) ternary eutectic alloy at different cooling rates and solid back diffusion coefficients, coupled with Thermo-Calc. It was indicated that the cooling rates ( ) had no obvious effect on the solidification path which was (L + α) → (L + α + T) → (L + α + β + T); but the solid back diffusion coefficient (Φ) had a great effect on the solidification path, which evolved gradually from (L + α) → (L + α + T) → (L + α + β + T) into (L + α) → (L + α + T) when Φ increased from 0 to 1. The volume fractions of primary α phase ( ), binary eutectic ( ) and ternary eutectic ( ) at each solidification path were calculated. It was shown that decreased with the increase of whereas increased and was almost invariant. The dependence of , and were determined by linear regression analysis given as: = −2.5lg + 47.5; = 6.4lg 47. Increase in Φ lead to increases in and and decrease in . The predicted soldification paths and volume fractions of Al-4.37Cu-27.02Mg ternary eutectic alloy at different cooling rates were in good agreement with experimental results.