(1. 湖南大學(xué) 汽車車身先進(jìn)設(shè)計(jì)制造國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410082；2. 湖南大學(xué) 機(jī)械與運(yùn)載工程學(xué)院，長(zhǎng)沙 410082)
摘 要: 采用改進(jìn)的Miedema模型和Eyring模型，對(duì)Al-2%Cu合金的液相擴(kuò)散系數(shù)進(jìn)行理論計(jì)算，建立了二元合金液相擴(kuò)散系數(shù)的理論計(jì)算模型，解決實(shí)驗(yàn)難以測(cè)量液相擴(kuò)散系數(shù)導(dǎo)致數(shù)據(jù)匱乏的難題。在Eyring模型中，引入液態(tài)合金黏度—時(shí)間的變化曲線，替代原模型中的溶劑黏度數(shù)值，以進(jìn)一步提高計(jì)算結(jié)果的準(zhǔn)確性。在微觀組織模擬中，基于常規(guī)恒定液相擴(kuò)散系數(shù)模擬結(jié)果的柱狀晶比例為20.1%，而基于本研究計(jì)算所得的液相擴(kuò)散系數(shù)曲線模擬結(jié)果的柱狀晶比例為64.8%，更接近實(shí)驗(yàn)測(cè)得的柱狀晶比例58.1%，很好地驗(yàn)證了液相擴(kuò)散系數(shù)理論計(jì)算模型的可行性和準(zhǔn)確性。
關(guān)鍵字: Al-Cu合金；Miedema模型；Eyring模型；擴(kuò)散系數(shù)；微觀組織
（1. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China; 2. College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China）
Abstract:The liquid phase diffusion coefficient of Al-2%Cu alloy was calculated with the modified Miedema model and Eyring model, to further improve the accuracy. The mathematical model of liquid phase diffusion coefficient in binary alloy was established to resolve the lack of liquid phase diffusion coefficient data that are difficult to measure in the experiment. Instead of the solvent viscosity value, the viscosity—temperature curve of liquid alloy was introduced into the Eyring model to increase the accuracy of calculation. In the microstructure simulation, the simulated proportion of columnar grains based on the normal constant liquid phase diffusion coefficient is 20.1%; while the proportion of columnar grains based on the calculated liquid phase diffusion coefficient with the developed model is 64.8%, which is much closer to the experimental result of 58.1%, indicating that the mathematical model of liquid phase diffusion coefficient is feasible and accurate.
Key words: Al-Cu alloy; Miedema model; Eyring model; diffusion coefficient; microstructure
