In situ observation of microstructural changes near the metal-ceramics interface during deformation

用透射电子显微镜（TEM）观察了金属与陶瓷界面附近的显微结构。特别注意的是，在使用各种技术的原位观察过程中，界面附近的微观结构的变化。试样制备的主要问题是金属和陶瓷材料的离子减薄速率差别很大。如果对初始试样盘进行机械预减薄和极化，则试样的质量可以得到显著改善。为了磨削试样中的半球形凹坑，研制了一种凹坑磨削装置。该装置由一个围绕水平轴旋转的砂轮组成，该砂轮放置在围绕水平轴旋转的样品平台上。金刚石复合物是砂轮所携带的磨削介质。X和Y测微计调整允许将样品定位在界面处， 关于我们 对不锈钢-氮化硼、铝合金-氮化硅、铝合金-碳化硅、钢-氮化钛等金属-陶瓷界面附近的显微组织进行了截面观察。变形后的Al-SiC复合材料的显微组织在铝合金基体界面附近有位错聚集。在SiC晶须中没有观察到位错活动。用于原位应变实验的样品可通过以下技术制备。样品的中心区域用离子研磨设备预减薄。在预减薄期间，旋转试样。然后通过离子研磨引入两个平行的凹坑（距离0.5mm）。在这部分减薄过程中，试样不旋转。通过平行于撞击离子束移动样品来调整凹坑的距离。最后的离子铣削是在样品旋转的同时进行的，直到在两个凹坑的区域中引入小孔。在金属界面附近原位观察到由应力引起的位错运动，但在陶瓷中没有观察到。少

The microstructure near the interfaces between metals and ceramics has been observed by transmission electron microscopy (TEM). Particular attention has been paid to the microstructural changes near the interface during in situ observations using various techniques.Specimens for TEM observations have been prepared by Ar ion-milling. The major problem of specimen preparetion is that the ion-thining rate is quite different between metallic and ceramic materials. The quality of specimens can be improved considerably if the starting specimen discs are mechanically pre-thinned and polised. In order to grind a hemispherical depression in specimens a dimple-grinding device has been made. This device consists of a grinding wheel rotating about a horizontal axis resting on a specimen platform rotating about a horizontal axis. Micron-sized diamond compounds are the grinding medium which is carried by the gringing wheel. X-and Y- micrometer adjustments allow positioning the specimen at the interf … More ace site on cross-sectional specimens.The cross-sectional observations of the microstructure near the metal-ceramics interface have been done on stainless steel-boron nitride, aluminum alloy-silicon nitride, aluminum alloy-silicon carbide and steel-titanium nitride. The microstructure of deformed Al-SiC composites shows dislocation accumulation near the interface in a matrix of aluminum alloy. Dislocation activities are not observed in SiC whiskers. The specimen for in situ straining experiments can be prepared by the following technique. The central area of the specimen is pre-thinned with an ion-milling apparatus. During the pre-thinning, the specimen is rotated. Two parallel dimples (distance 0.5 mm) are next introduced by ion-milling. The specimen is not rotated during this part of the thinning. The distance of the dimples is adjusted by displacing the specimen parallel tothe impining ion beam. The final ion-milling is performed while the specimen is rotated untile small holes is introduced in the area of the two dimples. Dislocation motion induced by stress is observed in situ near the interface in the metal but not in the ceramics. Less