高温合金气固复合深度脱硫的机理研究

解决或改善纯净度不高的瓶颈问题，是实现我国镍基高温合金材料自主化的关键所在。硫（S）是对高温合金影响最大的杂质元素，含量低于临界值（1ppm）会给合金服役条件下蠕变及抗氧化性能带来飞跃式提升。但目前国内尚无原创性的超低硫镍基高温合金制备工艺。.申请人提出“气固复合深度脱硫制备超低硫镍基高温合金”的新思路，拟通过镍基高温合金的氢气处理和氢化物原位反应两个工艺实现：氢气处理，将合金中的固态硫化物还原成气态脱硫产物排除体系；真空熔炼的过程中适当加入金属氢化物，原位生成高活性脱硫基元（Ce、La、Ca等）高效脱硫，而生成的氢气气泡及气态脱硫产物在排出熔体的过程中可以起到促进亚微米级固态脱硫产物上浮的作用。基于脱硫产物性态的转化，改变了传统固态脱硫产物“脱而不除”的现象和热力学极限的限制，实现了超低硫高温合金制备的原创性方案设计。该项目的实践有助于解决我国镍基高温合金纯净化程度低的瓶颈问题。

Solving or improving the bottleneck problem of low purity is the key to achieving the independence of my country's nickel-based superalloy materials. Sulfur (S) is the impurity element that has the greatest impact on superalloys, and the content below the critical value (1ppm) will bring a leap in the creep and oxidation resistance of the alloy under service conditions. However, there is currently no original preparation process for ultra-low sulfur nickel-based superalloys in China..A novel idea of "gas-solid composite deep desulfurization to prepare ultra-low sulfur nickel-based superalloys" was proposed. It is planned to be realized through two processes: hydrogen treatment and in-situ reaction of hydride of nickel-based superalloy: hydrogen treatment, which reduces the solid sulfide in the alloy into a gaseous desulfurization product elimination system. In the process of vacuum melting, metal hydride is appropriately added to generate highly active desulfurization elements (Ce, La, Ca, etc.) in situ for efficient desulfurization. The generated hydrogen bubbles and gaseous desulfurization products can play a role in promoting the floating of sub-micron solid desulfurization products during the process of discharging the melt. Based on the transformation of the properties of desulfurization products, the traditional solid-state desulfurization product "desulfurization but not removal" phenomenon and thermodynamic limitations have been changed, and the original design of the preparation of ultra-low sulfur superalloys has been realized. The practice of this project will help solve the bottleneck problem of low purity of domestic nickel-based superalloys.