【摘要】 铝合金广泛应用于航空航天、轨道交通、汽车轻量化等领域。半连续直接冷却铸造技术是制备大型铝合金铸锭的重要方法。在此制备工艺中热裂是较为严重的铸造缺陷,该缺陷的控制是制备优质大型铸锭的一项关键技术。针对半连续铸造的发展概况及热裂形成机理和预测模型进行了概述,分析了基于几种热裂判据的热裂敏感性计算结果并与铸造实践对比。结果表明没有任何热裂判据能够定量预测热裂的产生,在定性预测方面,RDG判据具有最大的应用潜力。提出了微观–宏观理论计算与先进观测手段集成的未来展望,在发展热裂判据时,应将相变动力学、断裂力学、流体传热以及合金热力学相结合,并考虑三维糊状区热裂形核–扩展–愈合的复杂机制。更多还原

【Abstract】 Aluminum alloys are widely used in aerospace, rail transportation, automobile lightweight and other fields. Semi-continuous direct cooling casting technology is an important method for preparing large aluminum alloy ingots. However, in this preparation process, hot tearing is a serious casting defect, and the control of hot tearing defects is a key technology for preparing high-quality large ingots. In this paper, the development overview of direct chill casting(DC casting), the formation mechanism and prediction model of hot tearing are summarized, and the calculation results of hot tearing susceptibility based on several hot tearing criterion are analyzed and compared with the casting practice. The results show that none of hot tearing criterion can quantitatively predict the occurrence of hot tearing. In terms of qualitative prediction, the RDG criterion has the greatest application potential. The future prospect of the integration of micro-macro theoretical calculations and advanced observation methods is proposed. When developing hot tearing criterion, multiphase mechanics, fracture mechanics, fluid flow and alloy thermodynamics should be linked, and the nucleation-expansionhealing complex mechanism in the three-dimensional pasty zone should be considered.更多还原