碳化硅（SiC）是先进核燃料领域中的重要材料。烧结制备、化学气相沉积制备和辐照行为是SiC材料研究中关注的重点。通过分子动力学模拟对SiC材料的烧结制备、化学气相沉积制备和辐照行为进行研究，可以在微观层面对先进核燃料领域中SiC材料的实验研究和工艺优化提供机理解释和方向指导。首先，研究了烧结助剂作用下的SiC纳米颗粒烧结制备过程。基于纳米颗粒尺寸-熔点关系和晶格尺寸理论，验证并发展了烧结助剂-SiC体系的新型势函数。对Al-Si-C元素体系、Ti-Si-C元素体系和V-Si-C元素体系进行了模拟和比较。详细研究了有/无Al的SiC纳米颗粒烧结演化过程，并与典型的烧结实验结果进行了比较。通过烧结颈生长、能量演化和原子扩散定量分析了纳米颗粒的烧结机理，并与传统烧结理论相联系。结果表明，Al是更好的SiC烧结助剂，分子动力学模拟可以用于筛选SiC烧结助剂。选择合适的温度有利于烧结助剂发挥更好的促进烧结效果。通过分子动力学模拟得到的各种烧结机理与传统烧结理论基本一致。接下来，研究了温度对SiC材料化学气相沉积制备过程的影响。基于密度泛函理论计算的成键能量，提出了一种基于能量的蒙特卡洛-分子动力学-化学气相沉积（EMC-MD-CVD）模型，用于模拟有界面参与的MTS制备SiC材料的化学气相沉积过程。从沉积效率和表面反应类型两个方面研究了气固界面的MTS沉积机理。通过气相产物演化研究了不同成分SiC沉积薄膜的形成机理。通过能量演化和原子结构演化研究了SiC沉积薄膜的结晶机理。结果表明，EMC-MD-CVD模型可以实现裂解-吸附-脱附-生长的化学气相沉积过程模拟，且在温度对SiC沉积薄膜成分的影响规律方面与实验结果吻合较好。适当升高温度有利于MTS的沉积和SiC沉积薄膜的结晶。最后，以TRISO颗粒SiC层为例研究了SiC材料的辐照行为。通过肿胀程度、密度、原子结构演化、点缺陷演化、载荷-深度曲线和应力应变分布详细考察了SiC层的辐照行为。结果表明，不同类型的SiC层受辐照影响规律类似。辐照过程中的非晶化存在晶体结构转化为中间态结构，再转化为非晶结构的过程。辐照剂量饱和会使离位阈值差异导致的各种点缺陷差异消失。非晶化和点缺陷演化倾向于从晶界附近开始发展。辐照后的SiC层在外力作用下的承受能力和塑性变形程度减小、应力应变分布紊乱。

Silicon carbide (SiC) is a kind of important material in the field of advanced nuclear fuel. The sintering preparation, chemical vapor deposition preparation, and irradiation behavior are the focus of SiC materials research, which can be studied by molecular dynamics simulation. It is helpful to provide mechanism explanation and direction guidance for experimental research and process optimization of SiC materials in the field of advanced nuclear fuel at the micro level.Firstly, the sintering process of SiC nanoparticles with additives is studied. a new potential function of the additive-SiC system is verified and developed based on the nanoparticle size-melting point relationship and the lattice size theory. The Al-Si-C element system, Ti-Si-C element system, and V-Si-C element system are simulated and compared. The sintering evolution process of SiC nanoparticles with/without Al is studied in detail and compared with the typical sintering experimental results. The sintering mechanism of nanoparticles is analyzed quantitatively by sintering neck growth, energy evolution, and atomic diffusion, which is related to the traditional sintering theory. The results show that Al is a kind of better SiC additive. Molecular dynamics simulation can be used to select SiC additives. An appropriate temperature is beneficial to the additives to promote the sintering better. The sintering mechanism obtained by molecular dynamics simulation is in good agreement with the traditional sintering theory.Next, the effect of temperature on the preparation process of SiC materials by chemical vapor deposition is studied. An energy-based Monte Carlo-molecular dynamics-chemical vapor deposition (EMC-MD-CVD) model is proposed to simulate the chemical vapor deposition process of SiC materials prepared by MTS with interface participation based on the bonding energy calculated by density functional theory. The MTS deposition mechanism of the gas-solid interface is studied by deposition efficiency and surface reaction type. The formation mechanism of SiC deposited film with different components is studied by gas phase product evolution. The crystallization mechanism of SiC deposited film is studied by energy evolution and atomic structure evolution. The results show that the chemical vapor deposition process of pyrolysis-adsorption-desorption-growth can be simulated by the EMC-MD-CVD model. The influence of temperature on the component of SiC deposited film is in good agreement with the experimental results. Appropriately increasing the temperature is beneficial to the deposition of MTS and the crystallization of SiC deposited film.Finally, the irradiation behavior of SiC materials is studied by taking the SiC layer of TRISO particles as an example. The irradiation behavior of the SiC layer is studied in detail by swelling degree, density, atomic structure evolution, point defect evolution, load-depth curve, and stress-strain distribution. The results show that the effects of irradiation on different types of SiC layers are similar. The amorphization process of crystal structure into intermediate state structure and then transforming into amorphous structure exists during the irradiation. The difference of various point defects caused by the difference of atomic threshold displacement energy disappears when the irradiation dose is saturated. The amorphization and point defect evolution tend to start from the vicinity of grain boundaries. After irradiation, the bearing capacity and plastic deformation degree of the SiC layer are reduced under external force. The distribution of stress and strain under external force is disordered.