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

利用透射电子显微镜（TEM）观察了金属与陶瓷界面附近的微观结构。在使用各种技术的现场观测中，特别注意了界面附近的微观结构变化。用氩离子铣削法制备了TEM观察用的试样。试样制备的主要问题是金属材料和陶瓷材料的离子稀释率差异很大。试样的质量可以大大提高，如果开始试样盘机械预薄和polized。为了磨削试样的半球形凹陷，制作了一种凹窝磨削装置。该装置包括一个绕水平轴旋转的砂轮，该砂轮置于绕水平轴旋转的试样平台上。微米级金刚石化合物是砂轮携带的磨削介质。x和Y-千分尺调整允许定位试样在界面上。对不锈钢-氮化硼合金、铝合金-氮化硅合金、铝合金-碳化硅合金和钢-氮化钛合金在金属-陶瓷界面附近的微观组织进行了截面观察。变形后的Al-SiC复合材料的显微组织表现为在铝合金基体界面附近位错积累。在SiC晶须中未观察到位错活动。原位应变试验试样可采用以下方法制备。用离子铣削装置预先削薄试样的中心区域。在预薄过程中，试样被旋转。两个平行的酒窝（距离0.5毫米）是接下来引入离子铣削。在这部分变薄过程中，试样不旋转。酒窝的距离是调整的位移试样平行于冲击离子束。最后的离子铣削是在试样旋转的同时进行的，直到在两个凹窝的区域引入小孔。应力引起的位错运动在金属界面附近的原位观察到，而在陶瓷中没有。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