本文選題：相場模型　切入點(diǎn)：CA-PF模型　出處：《南昌大學(xué)》2015年碩士論文

【摘要】：隨著科學(xué)技術(shù)的飛速發(fā)展,計(jì)算機(jī)技術(shù)也在日益進(jìn)步,這為我們的工程材料的數(shù)值模擬提供了發(fā)展平臺。本文基于元胞自動機(jī)和相場兩種數(shù)值模型的理論基礎(chǔ)耦合了一種新型的CA-PF模型,并對比了該模型和其他兩種模型的不同點(diǎn)。以相場模型為例,模擬了Al-4.5wt%Cu五晶粒分別在不同過冷度(△T=17.3K、△T=15.3K、△T=13.3K)和不同晶粒間距(Δx=21.21×10-6m、Δx=14.14×10-6m、Δx=7.07×10-6m)下的各晶粒的生長情況;以及對比了等溫和非等溫條件下中心晶粒的變化。結(jié)果表明:當(dāng)過冷度△T=13.3K和晶粒間距Δx=7.07×10-6m時,中心晶粒最易形成近球晶;且同等條件下,非等溫比等溫情況更易促使中心晶粒形成近球晶。以新建立的CA-PF模型為基礎(chǔ),模擬了Al-4.5wt%Cu二元合金在等溫情況下的枝晶生長形貌以及不同過冷度下枝晶的生長形貌差別。對比了新型CA-PF模型和PF模型、CA模型的形貌差別、計(jì)算時間效率以及界面擴(kuò)散層的不同。結(jié)果表明:CA-PF模型符合枝晶生長理論,且當(dāng)初始溫度T0=912K時出現(xiàn)二次枝晶臂。對比三種模型得出,PF模型的枝晶最為粗大,CA模型的枝晶最細(xì),CA-PF模型的枝晶形貌介于二者之間。時間效率對比中,CA模型所耗時間最少,PF耗費(fèi)時間最多,CA-PF介于其中。而界面層則是PF的最為光滑精確,CA-PF的界面不及PF光滑。
[Abstract]:With the rapid development of science and technology, computer technology is also increasingly advanced, This provides a development platform for numerical simulation of engineering materials. In this paper, a new CA-PF model is coupled based on the theory of cellular automata and phase field. The differences between the model and the other two models are compared. Taking the phase field model as an example, the growth of Al-4.5wt%Cu five grains at different undercooling degrees (T _ (17. 3) K, T _ (15. 3) K) and grain spacing (螖 x ~ (21) 21 脳 10 ~ (-6) m, 螖 x ~ (14) 脳 10 ~ (-6) m, 螖 x ~ (7) 7 脳 10 ~ (-6) m) is simulated. The changes of central grains under isothermal and non-isothermal conditions are compared. The results show that the center grains are most likely to form near spherulites when the undercooling degree Tn13.3K and the grain spacing 螖 x = 7.07 脳 10 ~ (-6) m, and under the same conditions, Non-isothermal conditions are more likely than isothermal conditions to promote the formation of near-spherulite in central grains, which is based on the newly established CA-PF model. The dendritic growth morphology of Al-4.5wt%Cu binary alloy under isothermal condition and the dendritic growth morphology at different undercooling degree were simulated. The morphology of new CA-PF model and PF model were compared with those of CA model. The calculated time efficiency and the interfacial diffusion layer are different. The results show that the 1: CA-PF model accords with the dendritic growth theory. The secondary dendritic arm appeared at the initial temperature T0 / 912K. The dendrite morphology of CA model of PF model was found to be the thickest than that of CA model, and the dendrite morphology of CA-PF model was between the two. The time consuming of CA model was compared with that of CA model. And the interface layer is the most smooth and accurate of PF. The interface of CA-PF is not as smooth as PF.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TG292

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本文編號：1677145