Si含量对(AlCrTiZrHf)-Si_x-N高熵薄膜微观结构和力学性能的影响

采用自制的复合靶材,通过直流磁控溅射技术,在单晶Si基片上沉积一系列不同Si含量的(AlCrTiZrHf)-Six-N高熵薄膜,并依次采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、高透射电子显微镜(HRTEM)和纳米压痕仪对薄膜进行表征和测试,研究Si含量对其微观结构和力学性能的影响。实验结果显示,(AlCrTiZrHf)N薄膜成柱状晶生长,并具有(111)晶面的择优取向。Si元素的掺入,使得原薄膜的(111)峰消失,(AlCrTiZrHf)-Six-N薄膜晶粒得到细化,同时生成网状非晶相,从而形成非晶包裹纳米晶的纳米复合结构。随着Si含量的增加,薄膜力学性能先上升后下降,这种趋势归因于所形成的纳米复合结构,并且当Si含量为8%(体积比)时,薄膜的硬度和弹性模量最高,分别为26.6和250.9GPa。

Effects of silicon content on the microstructure and mechanical properties of (AlCrTiZrHf)-Si_x-N high-entropy films

A series of (AlCrTiZrHf)-Six-N high entropy films with different silicon contents were deposited on monocrystalline silicon substrates by direct-current (DC) magnetron sputtering.The films were characterized by X-ray diffractometry (XRD),scanning electron microscopy (SEM),high resolution transmission electron microscopy (HRTEM),and nano-indentation techniques.The effects of the silicon content on the microstructures and mechanical properties of the films were investigated.The experimental results show that the (AlCrTiZrHf)N films grew in columnar grains and presented a (111) preferrential growth orientation.The addition of the silicon element leaded to the disappearance of the (111) peak and the grain refinement of the (AlCrTiZrHf)-Six-N films.Meanwhile,the reticular amorphous phase formed,thus developing the nanocomposite structure with the nanocrystallines encapsulated by the amorphous phase.With the increase of the silicon content,the mechanical properties first increased and then decreased.The maximal hardness and modulus of the films reached 26.6 and 250.9 GPa,respectively,with the silicon content (x) of 8at%.The strengthening effect of the (AlCrTiZrHf)-Six-N film could be mainly attributed to the formation of the nanocomposite structure.