c-AIN的生长对AIN/(Ti,Al)N纳米多层膜力学性能的影响

Influence of the growth of c-AIN on the mechanical properties of AlN/(Ti,Al)N nanomultilayers

采用反应磁控溅射制备了具有不同调制周期的AIN/(Ti,Al)N纳米多层膜,研究了亚稳相立方氮化铝(c-AIN)在纳米多层膜中的生长条件及其对薄膜力学性能的影响。结果表明:在小调制周期下AIN以立方结构存在,并与(Ti,Al)N层形成同结构共格外延生长,使纳米多层膜产生较大的晶格畸变。与此相应,AIN/(Ti,Al)N纳米多层膜硬度和弹性模量随调制周期的减小呈单凋上升的趋势,当调制周期小于8～10 nm时其增速明显增大,并在调制周期为1.3 nm时达到最高硬度29.0GPa和最高弹性模量383 GPa.AIN/(Ti,Al)N纳米多层膜的硬度和弹性模量在小调制周期时的升高与亚稳相c-AIN的产生并和(Ti,Al)N形成共格结构有关。

AIN/(Ti, AI)N nanomultilayers with various modulation periods were synthesized by reactive magnetron sputtering. X-ray diffraction analysis, high resolution transmission microscopy and nanoindentation technique were employed to characterize the microstructure and mechanical properties of these multilayers. The results show that AIN has cubic structure at small modulation period through coherent epitaxial growth on (Ti,AI)N layers. And there is a aobvious lattice distortion in the multilayers. Correspondingly, the hardness and elastic modulus of AIN/(Ti,AI)N multilayers increase with the decrease of modulation period monotonically. They increase much more quickly when the modulation periods are less than 8-10 nm and reach the maximal hardness (29 GPa) and elastic modulus (383 GPa) at the modulation period of 1.3 nm. The formation of the metastable c-AIN and a coherent structure with (Ti,AI)N are the two main reasons for the enhancement of hardness and elastic modulus of AIN/(Ti,AI)N multilayers.