【摘要】 钛合金熔模铸件广泛应用于航空航天领域，在制备过程中，钛与陶瓷型壳易发生反应，从而导致型壳开裂、铸件变形等问题。因此，开展型壳焙烧过程温度分布和变形行为研究，对于提升型壳性能、改善铸件质量具有重要意义。本工作采用改进的蒙特卡洛方法构建辐射传热模型，考虑热损伤影响，建立“热-力-损伤”力学本构模型，基于ABAQUS二次开发专用模拟软件，开展型壳焙烧过程数值模拟研究。对陶瓷型壳的关键热物性参数进行实验测试，为数值模拟提供数据支撑。通过平板试件对建立的模型进行实验验证，模拟和实验结果吻合较好。采用开发的模拟软件，对环形阶梯件陶瓷型壳不同方案焙烧过程温度分布和变形行为进行模拟研究，结果表明：焙烧过程中温度的不均匀分布会导致型壳变形甚至开裂，尤其在结构突出部位更为显著。此外，随着焙烧温度升高，型壳内部玻璃相黏度降低，也会加剧热应力积累和型壳局部变形。通过对陶瓷型壳焙烧过程温度与变形的模拟研究，为型壳焙烧工艺优化以及钛合金熔模铸件合格率提升提供理论依据和技术支撑。更多还原

【Abstract】 Titanium alloy investment castings are widely used in the aerospace industry. During the manufacturing process,titanium is prone to reacting with the ceramic shell,which leads to defects such as shell cracking and casting deformation. Therefore,it is important to investigate the temperature distribution and deformation behavior during the sintering process of ceramic shell to improve the performance of the ceramic shell and enhancing the quality of casting. An advanced Monte Carlo method is employed to establish the radiative heat transfer model. Additionally,considering the impact of thermal damage,a coupled thermo-mechanicaldamage constitutive model is established. A specialized simulation software is created through secondary development based on ABAQUS to investigate the sintering process of ceramic shell. Thermo-physical parameters of the ceramic shell are measured to provide data support for the simulations. The proposed models are experimentally validated using a flat-plate specimen, and experimental results agree well with the simulated outcomes. Using the developed software,a comprehensive study is conducted on the temperature distribution and deformation behavior of the ceramic shell in an annular-stepped specimen under various process schemes. The results indicate that a non-uniform temperature distribution during the sintering process is more likely to induce significant deformation and even cracking in the shells,particularly at structural protrusions. Moreover,as the sintering temperature rises,the decreased viscosity of the glassy phase in the ceramic shell will also intensify thermal stress accumulation and localized deformation. The simulation study on the temperature distribution and deformation behavior of the ceramic shell during the sintering process provides theoretical insights and technical support for optimizing the sintering process of the ceramic shell and improving the qualification rate of titanium alloy investment castings.更多还原