TiN/TiB2异结构纳米多层膜的共格生长与力学性能

采用多靶磁控溅射法制备了一系列具有不同TiB₂调制层厚度的TiN/TiB_{2纳米多层膜.利用x射线衍射仪、高分辨电子显微镜和微力学探针研究了TiB2层厚变化对多层膜生长结构和力学性能的影响.结果表明，在fcc-TiN层(111)生长面的模板 作用下，原为非晶态的TiB2层在厚度小于2.9nm时形成hcp晶体态，并与fcc-TiN 形成共格外延生长；其界面共格关系为{111}TiN//{0001}TiB2，〈110〉TiN//〈1120〉TiB2.由于共格界面存在晶格失配 度，多层膜中形成拉、压交变的应力场，导致多层膜产生硬度和弹性模量升高的超硬效应， 最高硬度和弹性模量分别达到46.9GPa和465GPa.继续增加TiB2层的厚度，TiB2形成非晶态并破坏了与TiN层的共格外延生长，多层膜形成非晶TiN层和非晶TiB< sub>2层交替的调制结构，其硬度和弹性模量相应降低.关键词：2}纳米多层膜')" href="#">TiN/TiB₂纳米多层膜共格生长晶体化力学性能

The coherent growth and mechanical properties of non-isostructural TiN/TiB2 nanomultilayers

TiN/TiB₂ nanomutlialyers with different TiB₂ layer thickne ss were prepared using multi-target magnetron sputtering method. The effects of TiB₂ layer thickness on the growth structure and mechanical properti es of nanomultialyers were studied by X-ray diffraction, high-resolution transmi ssion electron microscopy and nanoindentation respectively. The results reveal t hat the normally amorphous TiB₂ layers crystallize in close-packed he xagonal structure when its thickness is less than 2.9 nm due to the template eff ect of cubic TiN layers. Coherent growth is found between TiN and TiB₂ layers with the orientation relationship of {111}_TiN//{0001}_{Ti B2,〈110〉TiN//〈1120〉TiB2. Because of th e lattice misfit, an alternating tensile/compressive stress field develops in th e nanomultilayers, which leads to the anomalous enhancement of hardness and elas tic modulus. Maximum hardness and elastic modulus of 46.9 and 465GPa are obtaine d at TiB2 layer thickness of 0.6nm. With increasing TiB2 l ayer thickness, amorphous TiB2 forms and blocks the coherent growth of the multilayers. Consequently, the hardness and elastic modulus of the films decrease gradually.}