Jing Huang, Vitaly E. Gruzdev, Yuwen Zhang^*, J. K. Chen

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-5, 2014, DOI:10.5098/hmt.5.1

Abstract Experimental study on laser sintering of nanosized titanium and nickel powders using a nanosecond laser is reported in this paper. Pulse laser with a wavelength of 532 nm and pulse width (FWHM) of 23 nanoseconds is used. The diameters of the metal nanoparticles are between 35 to 50 nanometers. Pulse repetition rates range between 100 and 10,000 Hz and the average power is from 1 to 20 W. The powder bed is placed on a moving stage to control the scanning velocity. Sintered metal strips with 20 mm length are formed by focusing the laser beam on the surface of… More >

Xueling Fan^1,*, Pin Lu¹, Xiaochao Jin¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.2, pp. 1-1, 2023, DOI:10.32604/icces.2023.09919

Abstract Ni-based single crystal superalloys have been favored in the high-temperature service zones of aeroengine and gas turbine due to its excellent mechanical properties at high temperature. It is very significant to construct a constitutive model that can accurately capture the mechanical response of Ni-based single crystals for simulation analysis. In this work, a forest dislocation density-based single crystal plasticity constitutive model was developed to capture the mechanical behavior of Ni-based single crystals, including the temperature dependent anomalous yield and tension/compression asymmetry. Firstly, thermally activated cross-slip mechanism was introduced into the hardening model to describe the anomalous yield response. Secondly, the… More >

Zihang Li^1,#, Zexin Wang^1,#, Zi Wang², Zijun Qin¹, Feng Liu¹, Liming Tan^1,*, Xiaochao Jin^3,*, Xueling Fan³, Lan Huang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.135, No.2, pp. 1521-1538, 2023, DOI:10.32604/cmes.2022.021639

Abstract Solid solution strengthening (SSS) is one of the main contributions to the desired tensile properties of nickel-based superalloys for turbine blades and disks. The value of SSS can be calculated by using Fleischer’s and Labusch’s theories, while the model parameters are incorporated without fitting to experimental data of complex alloys. In this work, four diffusion multiples consisting of multicomponent alloys and pure Ni are prepared and characterized. The composition and microhardness of single γ phase regions in samples are used to quantify the SSS. Then, Fleischer’s and Labusch’s theories are examined based on high-throughput experiments, respectively. The fitted solid solution… More >

P. Sittisart^1,*, M.M. Hyland¹, M.A. Hodgson¹, C. Nguyen², A. Fernyhough³

Journal of Renewable Materials, Vol.2, No.4, pp. 264-269, 2014, DOI:10.7569/JRM.2014.634123

Abstract A series of composites based on polypropylene with different loadings of nickel-coated cellulose fi bres (NCCF) were fabricated with the aim to create a composite suitable for EMI shielding and/or electrostatic discharge application. Various properties such as EMI shielding effectiveness, surface resistivity, volume resistivity and fl exural strength were characterised according to ASTM standard. Both surface and volume resistivity suggested that the electrical conductivity of NCCF was not high enough and the composite remains electrically non-conducting up to 40 wt% loading of NCCF. However, nickel particles were still able to shield electromagnetic radiation regardless of their connectivity and conductivity. This… More >

Daniel Varadaradjou^1,*, Hocine Kebir¹, Jérôme Mespoulet², David Tingaud³, Salima Bouvier¹, Paul Deconick², Kei Ameyama⁴, Guy Dirras^3,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.24, No.1, pp. 1-3, 2022, DOI:10.32604/icces.2022.08673

Abstract The development of new architecture metallic alloys with controlled microstructures is one of the strategic ways for designing materials with high innovation potential and, particularly with improved mechanical properties as required for structural materials [1]. Indeed, unlike conventional counterparts, metallic materials having so-called harmonic structure displays strength and ductility synergy. The latter occurs due to a unique microstructure design: a coarse grain structure surrounded by a 3D continuous network of ultra-fine grain known as “core” and “shell”, respectively. In the present study, pure harmonic-structured (HS) Nickel samples were processed via controlled mechanical milling and followed by spark plasma sintering (SPS),… More >

Yabin Xu^1,*, Lulu Cui¹, Xiaowei Xu²

Computer Systems Science and Engineering, Vol.42, No.1, pp. 121-132, 2022, DOI:10.32604/csse.2022.022758

Abstract Fracture toughness plays a vital role in damage tolerance design of materials and assessment of structural integrity. To solve these problems of complexity, time-consuming, and low accuracy in obtaining the fracture toughness value of nickel-based superalloys through experiments. A combination prediction model is proposed based on the principle of materials genome engineering, the fracture toughness values of nickel-based superalloys at different temperatures, and different compositions can be predicted based on the existing experimental data. First, to solve the problem of insufficient feature extraction based on manual experience, the Deep Belief Network (DBN) is used to extract features, and an attention… More >

Liefei Pei, Xiangyun Zhang, Zizhou Yuan^*

Journal of Renewable Materials, Vol.10, No.4, pp. 955-968, 2022, DOI:10.32604/jrm.2022.016961

Abstract Fe-Si-B amorphous zero-valent iron has attracted wide attention because of its efficient remediation of heavy metals and dye wastewater. In this paper, the remediation effect of amorphous zero-valent iron powder (Fe₇₈Si₉B₁₃^AP) on Ni contaminated soil was investigated. Results show that the immobilization efficiency of nickel in soil by Fe₇₈Si₉B₁₃^AP with low iron content is higher than that by ZVI. The apparent activation energies of the reactions of Fe₇₈Si₉B₁₃^AP with Ni²⁺ ions is 25.31 kJ/mol. After continuing the reaction for 7 days, Ni²⁺ ions is mainly transformed into monoplasmatic nickel (Ni⁰) and nickel combined with iron (hydroxide) oxides. Microstructure investigations show… More >

Ramana M. Pidaparti¹, Alex C. Johnson¹

Structural Durability & Health Monitoring, Vol.9, No.1, pp. 87-98, 2013, DOI:10.32604/sdhm.2013.009.087

Abstract Surface damage in the form of pitting was observed in NiAl Bronze metal subjected to corrosion and cyclic stresses. In order to investigate the stresses surrounding the evolving pits due to corrosion, an image based computational study was carried out. The computational study involves developing an analysis model from the SEM images of corroded pits and then conducting stress analysis. Several computational simulations were carried out with increasing/evolving pits and the corresponding stress environment was obtained. The results obtained indicate that pit profiles (size and height) greatly affect the stress environment and the maximum stresses may vary depending on the… More >

Wen-Ping Wu^1,2, Zong-Zhuan Yao³

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.4, pp. 235-252, 2013, DOI:10.3970/cmes.2013.093.235

Abstract The internal microstructure evolution and atomic stress distribution around the crack tip of a pre-cracked single crystal nickel with unequal sample sizes are studied by molecular dynamics (MD) simulation. The simulated results indicate that the crack propagation dynamics and stress distributions around the crack tip are strongly dependent on the microstructure evolution caused by the change of sample size. Unequal sample sizes induce various atomic configurations around the crack tip during the crack propagation. When atomic configuration is invariable around the crack tip, the crack grows rapidly along the crack path, the stress concentration occurs at the crack tip of… More >

Arun K. Nair¹, Diana Farkas², Ronald D. Kriz¹

CMES-Computer Modeling in Engineering & Sciences, Vol.24, No.2&3, pp. 239-248, 2008, DOI:10.3970/cmes.2008.024.239

Abstract The indentation response of Ni thin films of thicknesses in the nano scale was studied using molecular dynamics simulations with embedded atom method (EAM) interatomic potentials. Simulations were performed in single crystal films in the [111] orientation with thicknesses of 7nm and 33nm. In the elastic regime, the loading curves observed start deviating from the Hertzian predictions for indentation depths greater than 2.5% of the film thickness. The observed loading curves are therefore dependent on the film thickness. The simulation results also show that the contact stress necessary to emit the first dislocation under the indenter is nearly independent of… More >