Structure, deformation and fracture of arc evaporated Zr-Si-N hard films
Structure, deformation and fracture of arc evaporated Zr-Si-N hard films
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DOI：
10.1016/j.surfcoat.2014.07.024
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发表时间：
2014-11
影响因子：
5.4
通讯作者：
K. Yalamanchili;Rikard Forsén;E. Jiménez-Piqué;M. Jõesaar;J. Roa;N. Ghafoor;M. Odén
中科院分区：
文献类型：
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作者：
K. Yalamanchili;Rikard Forsén;E. Jiménez-Piqué;M. Jõesaar;J. Roa;N. Ghafoor;M. Odén
通过反应阴极电弧沉积技术，在 WC-Co 基底上生长了不同 Si 含量的 Zr-Si-N 薄膜。由此产生的薄膜微观结构与机械性能和变形机制的主要变化相关。 Si 在立方 ZrN 晶格中形成高达 1.8 at.% 的替代固溶体，呈现出精细的柱状微观结构。进一步添加 Si 会导致非晶 (a)-SiNx 相沉淀，并形成纳米复合材料微观结构 (ncZrN/a-SiNx)，在 Si 含量为 6.3 at.% 时完全抑制柱状微观结构。薄膜生长过程中旋转引起的人工分层被用作可视化薄膜变形的标记。基于位错的均匀塑性变形机制在柱状微观结构中占主导地位，而晶界滑动是介导纳米复合材料微观结构中非均匀塑性变形的主动机制。由于有效的固溶强化，薄膜硬度随着柱状微观结构中 Si 含量的增加而增加。纳米复合材料微观结构中局部晶界滑动的变形机制导致硬度较低。当压痕引起裂纹时，细柱状微观结构表现出明显的裂纹偏转，与纳米复合材料薄膜相比，导致更高的断裂阻力。
Zr–Si–N films with varying Si contents were grown on WC–Co substrates by reactive cathodic arc deposition technique. The resulting microstructures of the films correlate to dominant variation in mechanical properties and deformation mechanisms. Si forms a substitutional solid solution in the cubic ZrN lattice up to 1.8 at.% exhibiting a fine columnar microstructure. Further Si additions result in precipitation of an amorphous (a)-SiNxphase and evolution of a nanocomposite microstructure (ncZrN/a-SiNx) which completely suppresses the columnar microstructure at 6.3 at.% Si. The rotation-induced artificial layering during film growth is used as a marker to visualize the deformation of the film. A dislocation-based homogeneous plastic deformation mechanism dominates the columnar microstructure, while grain boundary sliding is the active mechanism mediating heterogeneous plastic deformation in the nanocomposite microstructure. Film hardness increases with increasing Si content in the columnar microstructure due to an effective solid solution strengthening. The deformation mechanism of localized grain boundary sliding in the nanocomposite microstructure results in a lower hardness. When cracking is induced by indentation, the fine columnar microstructure exhibits pronounced crack deflection that results in a higher fracture resistance compared to the nanocomposite films.