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为研究高分散陶瓷对金属薄膜的强化作用,通过Al和Ti B2靶磁控共溅射方法制备了不同Ti B2含量的铝基复合薄膜,采用X射线能量分散谱仪、X射线衍射仪、透射电子显微镜、扫描透射电子显微镜和微力学探针表征了薄膜的微结构和力学性能。结果表明:在溅射粒子的高分散性和薄膜生长的非平衡性共同作用下,Ti B2靶的溅射粒子被超过饱和地固溶于Al的晶格中,复合薄膜形成的固溶体兼具了置换和间隙2种固溶类型特征。在这种置换和间隙“双超过饱和固溶”的作用下,铝固溶体的晶格产生剧烈畸变,复合薄膜的晶粒在很低的溶质含量下就迅速纳米化,并在晶界区域形成溶质的富集区。随溶质含量的增加,晶界的宽化使复合薄膜逐步形成了极细纳米晶分布于非晶基体中的结构。与此相应,薄膜的硬度迅速提高并在含5.8%Ti B2时达到6.9 GPa的最高值,进一步提高Ti B2的含量,复合薄膜因逐渐非晶态而呈现硬度的降低。研究结果显示了高分散Ti B2的超过饱和固溶对铝基薄膜显著的晶粒纳米化作用和强化效果。
In order to study the strengthening effect of highly dispersed ceramic on metal thin films, aluminum-based composite films with different contents of TiB2 were prepared by magnetron sputtering method of Al and TiB2 targets. X-ray diffraction, X-ray diffractometer, Electron microscopy, scanning transmission electron microscopy and micro-mechanical probes were used to characterize the microstructure and mechanical properties of the films. The results show that the sputtered particles of TiB2 target are more than the saturation solid solution in the lattice of Al under the combined effect of the high dispersion of sputtered particles and the unbalanced growth of the films. The solid solution formed by the composite thin films combines Replacement and clearance of two kinds of solution type characteristics. In this displacement and the gap “double over the saturated solution ” under the action of the aluminum solid solution crystal lattice produced dramatic distortion, the composite film in the grain at a very low solute content rapidly nano-and in the grain boundary region The formation of solute enrichment zone. With the increase of solute content, the grain boundary widening makes the composite thin film gradually formed the structure of the ultrafine nanocrystal distributed in the amorphous matrix. Correspondingly, the hardness of the film increased rapidly and reached the highest value of 6.9 GPa with 5.8% TiB2, further increasing the content of TiB2, the hardness of the composite film decreased due to the gradual amorphous state. The results show that the over-saturating solid solution of highly dispersed TiB2 can significantly improve the effect of nanocrystallization and strengthening of aluminum-based films.