(1. 上海工程技術(shù)大學(xué) 材料工程學(xué)院，上海 201620；
2. 上海工程技術(shù)大學(xué) 汽車工程學(xué)院，上海 201620)
摘 要: 根據(jù)7050鋁合金單道次熱壓縮變形實驗數(shù)據(jù)，對建立微裂紋修復(fù)的元胞自動機(CA)模型所需相關(guān)參數(shù)進行辨識和計算。利用Microsoft Visual C++平臺編制了包含拓撲變形機制、位錯密度演變機制、動態(tài)再結(jié)晶動力學(xué)機制的沿晶微裂紋熱塑性修復(fù)的微觀組織CA演化規(guī)則。針對裂紋表面和母相晶界的不同特征，提出再結(jié)晶過程中表面能和晶界能驅(qū)動下不同的晶粒長大方式。CA模擬結(jié)果表明：一定條件下的熱塑性變形和動態(tài)再結(jié)晶可完全修復(fù)材料內(nèi)部微裂紋，且裂紋愈合過程中出現(xiàn)的分段愈合特征與實驗結(jié)果相吻合，但裂紋愈合的形貌演化取決于裂紋形態(tài)、裂紋表面形核率和形核位置、新晶粒長大方向與速度。
關(guān)鍵字: 鋁合金；微裂紋；熱塑性修復(fù)；動態(tài)再結(jié)晶；元胞自動機
（1. School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China;
2. School of Automotive Engineering, Shanghai University of Engineering Science, Shanghai 201620, China）
Abstract:According to experimental data of 7050 aluminum alloy in single-pass hot compression, the relevant parameters of cellular automaton (CA) model for microcrack healing were identified and calculated. Using Microsoft Visual C++ platform, the CA rules of microstructural evolution of intergranular microcrack during thermoplastic healing include topological deformation mechanism, the dislocation density evolution mechanisms and dynamic recrystallization kinetics mechanism were programmed. For the different characteristics of crack surface and grain boundary, the crack surface energy and grain boundary energy drive the growth of grain in different ways and the mechanism was proposed in the recrystallization process. The CA simulation results show that the hot thermoplastic deformation and dynamic recrystallization can repair microcracks completely under certain conditions, and the piecewise healing characteristics during crack healing process have a good agreement with the experimental results, but the appearance of crack healing depends on the crack morphology, crack nucleation rate and nucleation site, the growth direction and speed of new grain.
Key words: 7050 aluminium alloy; microcrack; thermoplastic repairing; dynamic recrystallization; cellular automaton
