Molybdenum (Mo) has been reported as a potential candidate for the diffusion barrier between U-10Mo fuel and AA6061 cladding in monolithic fuel plates. Interdiffusion and reaction between Al and Mo was investigated using solid-to-solid diffusion couples annealed in the temperature range from 425° to 625 °C. Thermo-kinetic parameters, i.e. growth rate and integrated diffusion coefficients, were determined using Wagner's approach. At low temperatures (T ≤ 450 °C), negligible diffusion interaction was observed between Al and Mo. At intermediate temperatures (T = 475° - 600 °C), diffusion couples were observed to mainly develop a layer of Al₈Mo₃ intermetallic phase, along with a thin, discontinuous layer of Al₂₂Mo₅ intermetallic phase between the terminal Al and Al₈Mo₃ layer. At high temperature (T = 625 °C), continuous layers of both of Al₈Mo₃ and Al₂₂Mo₅ intermetallic phases developed in the diffusion couple. The Al₈Mo₃ phase grew with a needle-like, non-planar morphology at intermediate temperatures, contrary to the planar growth of the intermediate phase in binary diffusion couple as per Gibbs phase rule. In general, the degree of non-planarity of needle-like Al₈Mo₃ phase increased with an increase in annealing time at 500 °C, but decreased with an increase in annealing temperature. This non-planar growth was simulated based on three-dimensional anisotropic diffusion using a quadric representation of the diffusivity tensor.

钼（Mo）已被报告为整装燃料板中U-10Mo燃料和AA6061覆层之间扩散障碍的潜在候选者。使用在425°至625°C温度范围内退火的固-固扩散偶研究了Al和Mo之间的相互扩散和反应。使用Wagner方法确定热动力学参数，即生长速率和积分扩散系数。在低温（T≤450°C）下，Al和Mo之间的扩散相互作用可忽略不计。在中间温度（T = 475°-600°C）下，观察到扩散偶主要形成一层Al ₈ Mo ₃金属间化合物相，以及不连续的Al ₂₂ Mo ₅薄层Al和Al ₈ Mo ₃层之间的金属间相。在高温（T = 625°C）下，在扩散对中形成了Al ₈ Mo ₃和Al ₂₂ Mo ₅金属间相的连续层。Al ₈ Mo ₃相在中间温度下以针状，非平面形态生长，这与按照吉布斯相规则在二元扩散偶中的中间相的平面生长相反。通常，针状Al ₈ Mo ₃的非平面度在500°C下，随着退火时间的增加，相的数量增加，而随着退火温度的增加，相的数量减少。基于三维各向异性扩散，使用扩散率张量的二次表示模拟了这种非平面增长。