Nanoscale elastic‐plastic deformation and mechanical properties of 3C‐SiC thin film using nanoindentation

Abstract

The elastic-plastic deformation of 3C-SiC thin film was investigated by a nanoindenter equipped with the Berkovich tip. Transition from pure elastic to elasticplastic deformation was evidenced at an approximate load of 0.35 mN, when loading the sample at several peak loads ranging from 0.5 to 5 mN. The indentation size effect observed in 3C-SiC and was analyzed by Nix-Gao model. In purely elastic region, the Oliver-Pharr hardness values were 44 ± 2 GPa. In contrast, indentation size effects were evidenced in 3C-SiC specimen and the average value of Oliver-Pharr hardness in the indentation size effect region was 36 ± 2 GPa. Furthermore, depth independent or intrinsic hardness extracted from Nix-Gao was estimated as H o = 26 ± 1 GPa which was also validated by proportional specimen resistance model, ie, H 1 = 28 ± 1 and H 2 = 28.5 ± 0.1 GPa.Besides, energy principle was utilized to extract Sakai Hardness as 104 GPa, which is combined elastic and elastic-plastic response. Moreover, based on energy principle, another property, ie, work of indentation was also determined to be 20 nJ/μm 3 . Similarly, elastic modulus had almost depicted stabilized value of 325 ± 8 GPa in pure elastic and elastic-plastic regions. In addition, plastic zone size was also estimated in elastic-plastic region using Johnson cavity model at pop-in and higher loads. Based on the first pop-in load at 0.35 mN, the distributions of shear and principal stresses were evaluated on various slip planes to elaborate the deformation behavior. Increase in loading rate from 100 to 400 μN/s increased critical pop-in load from 0.35 to 0.64 mN. This increase in critical popin load with increasing loading rate and values of maximum contact pressure indicates that no phase assisted transformation will occur at pop-in load. Based on theoretically calculated maximum tensile and cleavage strengths, it was affirmed that the elastic-plastic deformation occurred due to pop-in formation rather than tensile stresses. Moreover, it was also concluded on basis of Hertzian contact theory and Schmidt law that the highest possibility of slippage in 3C-SiC was along the {111} glide plane. K E Y W O R D S

Finite Element Modeling of Brittle and Ductile Modes in Cutting of 3C-SiC

“…The analysis of the simulation results with the Oliver-Pharr method yielded values of Young's modulus and hardness of 446 GPa and 40 GPa, respectively, which is within ≈2% of the experimental values. Similar values of Young's modulus and hardness have been reported by Nawaz et al [33].…”

“…The initial load-depth curve shows a behavior of P ∝ h 3/2 , where P is the load, and h is the depth, indicating an elastic Hertzian contact at small depths. For validation purposes, the Young's modulus and the hardness were calculated from the unloading stage of the load-depth curves using the Oliver-Pharr method [31,32], which has been widely used to identify these material parameters [29,33]. The experimentally derived Young's modulus and hardness were 440 GPa and 39 GPa, respectively.…”

Cracks Forming and Propagation Mechanism for the Q345 Steel during Cooling

“…Nowadays, Nano indenter measurement has been widely used to investigate materials properties [17][18][19][20] . The advantage of nanoindentation technology over conventional methods is that it can provide micro mechanical properties of the material accurately.…”

Molecular dynamics simulation of mechanical strengthening properties of SiC substrate covered with multilayer graphene

“…Li等 [15] 实验研究表明: 石墨烯/SiC复合材 料的致密度随着石墨烯含量增大而降低, 通过添加 少量石墨烯, 石墨烯/SiC复合材料的弯曲强度及 断裂韧性得到极大改善, 但是当石墨烯添加过量 时, 石墨烯/SiC复合材料的弯曲强度和断裂韧性 确呈现逐渐下降趋势 [16][17][18][19] . 李炯利等 [20] 采用实验 法研究了石墨烯增强铝基复合材料的力学性能, 指 出静态载荷下添加石墨烯的铝基复合材料屈服强 度虽然可以提高, 但缺乏对材料塑性变形的微观理 解. 另外, Nawaz等 [21] 对3C-SiC的纳米压痕展开 实验研究, 发现在塑性变形阶段, 位错滑移方向沿 {111}晶面系族, 也有学者 [22][23][24][25] 报道了SiC材料的 位 错 滑 移 和 非 晶 态 产 生 所 致 的 塑 性 变 形 行 为 .…”