U-10Mo/Al-Si固体扩散行为

采用扩散偶方法研究U-10Mo合金与Al-xSi(x＝0，1，2，5，7，9，质量分数)合金的固体扩散行为。实验在真空热压炉中完成，退火温度为555、570、580、590和595℃，时间为5～10h。实验结果表明：退火条件对扩散行为有显著影响，580℃是U-10Mo/Al-xSi扩散行为的重要分界点；当温度低于580℃热压退火处理时，扩散层厚度随Si含量的增加先急剧减小然后缓慢增大；当温度高于580℃时，扩散层的厚度随Si含量的增加而增加。Si含量较高(≥2%)的扩散偶扩散层厚度比低Si含量的小，扩散层呈3层结构，靠近Al-Si侧出现贫Si区。成分分析显示：Si含量较高的扩散偶，靠近U-Mo侧的扩散薄层中出现Si的富集，其成分为(U，Mo)(Al，Si)_x (x≤3)；靠近Al-Si合金侧的扩散层成分为(U，Mo)(Al，Si)_x (x＞3)。

Diffusion Behavior on U-10Mo/Al-Si Alloys

The diffusion behavior between U-10Mo and Al-Si alloys was studied with diffusion-couple method. The couple was annealed in a high vacuum heat-pressure furnace at 555, 570, 580, 590 and 595 ℃, respectively for 5-10 h. Annealing conditions have a significant effect on interaction-layer thickness. When temperature is lower than 580 ℃ with pressuring, the thickness suddenly decreases then slowly increases with the Si content increasing; however, when temperature is higher than 580 ℃ the thickness increases with the Si content increasing. Interaction layer with higher Si content which thickness is lower than that with lower Si content is composed of three layers. Si-rich layer with the composition of (U, Mo)(Al, Si)_x(x≤3) closes to U-lOMo side, Si-poor layer with the composition of (U, Mo)(Al, Si)_x(x>3) closes to Al-Si side.