Determination of mechanical properties of Bi12TiO20 crystals by nanoindentation

Isik, M.; Gasanly, Nizami; Rustamov, F. A.

doi:10.1016/j.mssp.2021.106389

Cited by 5 publications

(2 citation statements)

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“…), DSNI is a type of quantitative method for characterizing the nanoscale mechanical properties of substrate materials (Nili et al, 2013). So far, DSNI has already been applied for studying the mechanical properties of lots of materials, including composites, polymers, metals, and crystals (Sankaran et al, 2018;Yuemin Wang et al, 2020;Han et al, 2021;Isik et al, 2022). In recent years, this technology has received increased attention in coal research (Vranjes et al, 2018;Zhang et al, 2018;Sun et al, 2020a;Sun et al, 2020b;Kossovich et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation of the Nanoindentation of Coal Vitrinite

2022

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Coal deformation is closely correlated with the distribution of organic maceral groups, however, molecular dynamics (MD) simulations of vitrinite nanoindentation have rarely been conducted. In this study, the vitrinite substrate for indentation was constructed utilizing polymer consistent force field (PCFF), and a spherical ghost indenter was used for loading. The results showed that: 1) In the indentation process, some of the vitrinite atoms overcame the energy barrier to move, with the most important deformation mechanism including the sliding, bending, and reorientation of vitrinite molecular chains, leading to the formation of a shearing transformation zone (STZ), which was also found to contain structural defects and stacking of aromatic structures. 2) The distribution of atomic displacements in the vitrinite substrate could be subdivided into distinct regions, with slippage at the region boundaries producing shear bands. 3) The surface morphology and mechanical properties obtained from the nanoindentation simulation were similar to experimental results from the literature, indicating that MD simulations are a powerful tool for studying coal nanoindentation. The results from this study increase the current scientific understanding of the mechanical properties of vitrinite by providing a new perspective that elucidates the nanoscale structural evolution occurring during the indentation process.

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Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation of the Nanoindentation of Coal Vitrinite

2022

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“…With the fast development in the fabrication of structures on the functional materials used in aerospace engineering, renewable energy engineering, and microelectronics engineering, the characterization of material properties at the microscale and nanoscale levels must be accurately obtained (Reggente et al, 2020;Hossain et al, 2022). Currently, nanoindentation is considered a powerful technique used to quantitatively characterize the mechanical properties of different kinds of materials (Das et al, 2022), and by fitting the appropriate models to the curve of force with respect to displacement obtained from the test, the major material properties, such as the elastic modulus, hardness, and fracture toughness can be measured at the microscale and nanoscale (Isik et al, 2022;Song et al, 2022). Since the indentation depths are in the order of nanometers, the surface quality of the sample has an essential effect on the nanoindentation test (Chen et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Optimization of Lapping and Polishing of Steel Samples for Nanoindentation Based on SVM-GA

Cheng

2022

Front. Mater.

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The nanoindentation test is extensively used to obtain the mechanics performance of different kinds of materials. In this study, the general process in the lapping and polishing of Q235 steel samples for nanoindentation has been analyzed by considering the pressure (P), rotation speed of the lapping and polishing plate (rp), flow rate of abrasive slurry (Qa), and the processing time (t). It is found from the lapping experiments with a full factorial design that the optimized processing parameters are rp of 200 r/min, P of 30 N, and t of 4 min considered in this study by considering the material removal rate and subsurface damage. The central composite design method has been used to design the polishing experiments, and the support vector machine (SVM) method has been used to deal with these experimental results, and it is found that the developed SVM model can accurately predict the surface roughness under different processing parameters. Then, based on the SVM model, the genetic algorithm (GA) method is used to obtain the optimized processing parameters in the polishing process, and it is found from the SVM-GA study that the optimized processing parameters in the lapping process are rp of 108 r/min, P of 33 N, Qa of 20 ml/min, and t of 3 min. Finally, a set of nanoindentation tests have been conducted to evaluate the lapping and polishing performance, and it is found that the surface integrity has been significantly improved after the optimization of the lapping and polishing parameters by using the SVM-GA method considered in this study.

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