本文提出一种新的X射线形貌法,并利用它观察三点弯曲Mo单晶的断口特征及其断裂过程。从断口X射线衍射像中不但看到同金相断口一样的分区,即失稳扩展区、稳态扩展区和由撕裂形成的三角区;还显示出亚晶粒及其取向、亚晶粒破碎同应力状态等。从断裂过程的研究中可观察到预裂纹前方亚晶粒的转动、晶面的弯曲和范性区的扩展过程等。 In this paper, a new X-ray topography method is proposed and used to observe the fracture characteristics and fracture process of three-point bending Mo single crystal. From the fracture X-ray diffraction image not only saw the same fracture with the metallurgical phase, ie, instability expansion zone, the steady-state expansion zone and tear formed by the triangle; also showed subgrain and its orientation, subgrain Broken with the stress state. From the study of the fracture process, the subgrain rotation in front of the pre-crack, the warping of the crystal plane and the expansion of the vanity zone can be observed.