Sn-Pb合金枝晶生长的同步辐射X射线衍射增强成像研究

Sn-Pb alloy dendritic growth by XRD-enhanced imaging at BSRF

用北京同步辐射光源X射线衍射增强成像法对Sn-Pb金属合金的结晶过程进行实时成像研究,成功地获得枝晶生长行为及形貌演变的系列动态图像,为研究金属合金结晶理论提供直接的实验数据。实验观察到接近共晶成分的Sn-50wt.%Pb合金,在一定的温度梯度和冷却速率下呈现先等轴晶后柱状晶形貌生长。同步辐射X射线衍射增强成像技术为原位研究不透明的金属合金枝晶生长过程提供了崭新的实验手段,为验证或完善金属合金结晶过程的微观动力学模型提供了有效途径。

Real-time dendrite growth of Sn-Pb binary alloy was observed with diffraction-enhanced imaging method at Beijing Synchrotron Radiation Facility （BSRF）, and a series of time-sequenced images of the growth behavior and morphology evolution of dendrites were successfully obtained. These can offer the direct proofs to verify or improve the solidification theories of metallic alloy. The Sn-50wt%Pb alloy （near eutectic composition） grew in a manner with equiaxed first and then columnar dendritic morphology. This work provides a new approach for the study of alloy solidification and enables people have better understanding of alloy solidification processes. It is feasible to validate or complete the crystallization dynamics of metallic alloy by diffraction-enhanced imaging method.