Effect of coating thickness on the deformation mechanisms in PVD TiN-coated steel
Effect of coating thickness on the deformation mechanisms in PVD TiN-coated steel
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DOI：
10.1016/j.surfcoat.2009.11.008
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发表时间：
2010-02-25
影响因子：
5.4
通讯作者：
Munroe, P. R.
中科院分区：
文献类型：
--
作者：
Ma, L. W.;Cairney, J. M.;Munroe, P. R.
使用聚焦离子束 (FIB) 横截面和成像以及压痕区域的横截面透射电子显微镜 (TEM) 对纳米压痕后沉积在 V820 钢基材上的一系列不同厚度的 TiN 涂层的变形机制进行了表征。研究了四种TiN涂层，包括厚度约为0.7μm的阴极电弧蒸发(CAE)涂层和厚度约为2.0、3.7和4.0μm的低压电子束(LVEB)蒸发涂层。根据Xie等人建立的模型，计算出相似0.7、相似2.0、相似3.7和相似4.0μm厚的TiN涂层的柱间剪应力分别约为2.20、3.05、3.50和3.55 GPa，即随着涂层厚度的增加而增加。在较薄的 TiN 涂层中更频繁地观察到涂层/基体界面处的柱状裂纹和剪切台阶，这表明这些涂层主要通过沿柱状晶界的剪切而变形。相比之下，倾斜裂纹是较厚 TiN 涂层中更主要的断裂类型。这表明，由于更等轴的晶粒结构，晶界强度增加，同时缺乏沿着晶界穿过较厚涂层的直接裂纹路径。显然，TiN 涂层的晶粒结构和/或厚度在变形机制中起着非常重要的作用。 (C) 2009 Elsevier B.V. 保留所有权利。
The deformation mechanisms of a range of TiN coatings with different thicknesses, deposited on a V820 steel substrate following nanoindentation were characterized using focused ion beam (FIB) cross-sectioning and imaging, as well as cross-sectional transmission electron microscopy (TEM) of the indented region. Four TiN coatings were examined, including a cathodic arc evaporation (CAE) coating with a thickness of similar to 0.7 mu m and low voltage electron beam (LVEB) evaporation coatings with thicknesses of similar to 2.0, similar to 3.7 and similar to 4.0 mu m. Based on a model developed by Xie et al., the intercolumnar shear stresses were calculated to be approximately 2.20, 3.05, 3.50 and 3.55 GPa in the similar to 0.7, similar to 2.0, similar to 3.7 and similar to 4.0 mu m thick TiN coatings respectively, that is, increasing as the coating thickness increases. Columnar cracking and shear steps at the coating/substrate interface were observed more frequently in the thinner TiN coatings indicated that these coatings deformed predominantly by shear along the columnar grain boundaries. In contrast, inclined cracking was the more dominant fracture type in the thicker TiN coatings. It is suggested that increased grain boundary strength occurs together with a lack of direct crack path along the grain boundaries through the thicker coatings due to the more equiaxed grain structure. Clearly, the grain structure and/or thickness of the TiN coating play a highly significant role in the deformation mechanisms. (C) 2009 Elsevier B.V. All rights reserved.