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Title: Effects of Bi Addition on the Microstructure and Mechanical Properties of Nanocrystalline Ag Coatings

Abstract

Here in this study we investigated the effects of Bi addition on the microstructure and mechanical properties of an electrodeposited nanocrystalline Ag coating. Microstructural features were investigated with transmission electron microscopy (TEM). The results indicate that the addition of Bi introduced nanometer-scale Ag-Bi solid solution particles and more internal defects to the initial Ag microstructures. The anisotropic elastic-plastic properties of the Ag nanocrystalline coating with and without Bi addition were examined with nanoindentation experiments in conjunction with the recently-developed inverse method. The results indicate that the as-deposited nanocrystalline Ag coating contained high mechanical anisotropy. With the addition of 1 atomic percent (at%) Bi, the anisotropy within Ag-Bi coating was very small, and yield strength of the nanocrystalline Ag-Bi alloy in both longitudinal and transverse directions were improved by over 100% compared to that of Ag. On the other hand, the strain-hardening exponent of Ag-Bi was reduced to 0.055 from the original 0.16 of the Ag coating. Furthermore, the addition of Bi only slightly increased the electrical resistivity of the Ag-Bi coating in comparison to Ag. Lastly, results of our study indicate that Bi addition is a promising method for improving the mechanical and physical performances of Ag coating for electricalmore » contacts.« less

Authors:
ORCiD logo [1]; ORCiD logo [2];  [3];  [4];  [5];  [3]
  1. Jiangsu Univ. of Science and Technology, Jiangsu (China). School of Materials Science and Engineering; Univ. of Auckland, Auckland (New Zealand). Dept. of Chemical & Materials Engineering
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical and Computational Sciences Directorate
  3. Univ. of Auckland, Auckland (New Zealand). Dept. of Chemical & Materials Engineering
  4. Jiangsu Univ. of Science and Technology, Jiangsu (China). School of Materials Science and Engineering
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1390442
Report Number(s):
PNNL-SA-126344
Journal ID: ISSN 1996-1944; VT0505000
Grant/Contract Number:
AC05-00OR22725; AC06-76RL01830
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Materials
Additional Journal Information:
Journal Volume: 10; Journal Issue: 8; Journal ID: ISSN 1996-1944
Publisher:
MDPI
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Nanoindentation; Bi addition; nanocrystalline Ag; microstructure; electrical conductivity; mechanical properties; electrodeposited nanocrystalline Ag; nanoindentation

Citation Formats

Wang, Yuxin, Cheng, Guang, Tay, See Leng, Guo, Yuxia, Sun, Xin, and Gao, Wei. Effects of Bi Addition on the Microstructure and Mechanical Properties of Nanocrystalline Ag Coatings. United States: N. p., 2017. Web. doi:10.3390/ma10080932.
Wang, Yuxin, Cheng, Guang, Tay, See Leng, Guo, Yuxia, Sun, Xin, & Gao, Wei. Effects of Bi Addition on the Microstructure and Mechanical Properties of Nanocrystalline Ag Coatings. United States. doi:10.3390/ma10080932.
Wang, Yuxin, Cheng, Guang, Tay, See Leng, Guo, Yuxia, Sun, Xin, and Gao, Wei. 2017. "Effects of Bi Addition on the Microstructure and Mechanical Properties of Nanocrystalline Ag Coatings". United States. doi:10.3390/ma10080932. https://www.osti.gov/servlets/purl/1390442.
@article{osti_1390442,
title = {Effects of Bi Addition on the Microstructure and Mechanical Properties of Nanocrystalline Ag Coatings},
author = {Wang, Yuxin and Cheng, Guang and Tay, See Leng and Guo, Yuxia and Sun, Xin and Gao, Wei},
abstractNote = {Here in this study we investigated the effects of Bi addition on the microstructure and mechanical properties of an electrodeposited nanocrystalline Ag coating. Microstructural features were investigated with transmission electron microscopy (TEM). The results indicate that the addition of Bi introduced nanometer-scale Ag-Bi solid solution particles and more internal defects to the initial Ag microstructures. The anisotropic elastic-plastic properties of the Ag nanocrystalline coating with and without Bi addition were examined with nanoindentation experiments in conjunction with the recently-developed inverse method. The results indicate that the as-deposited nanocrystalline Ag coating contained high mechanical anisotropy. With the addition of 1 atomic percent (at%) Bi, the anisotropy within Ag-Bi coating was very small, and yield strength of the nanocrystalline Ag-Bi alloy in both longitudinal and transverse directions were improved by over 100% compared to that of Ag. On the other hand, the strain-hardening exponent of Ag-Bi was reduced to 0.055 from the original 0.16 of the Ag coating. Furthermore, the addition of Bi only slightly increased the electrical resistivity of the Ag-Bi coating in comparison to Ag. Lastly, results of our study indicate that Bi addition is a promising method for improving the mechanical and physical performances of Ag coating for electrical contacts.},
doi = {10.3390/ma10080932},
journal = {Materials},
number = 8,
volume = 10,
place = {United States},
year = 2017,
month = 8
}

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  • Here in this study we investigated the effects of Bi addition on the microstructure and mechanical properties of an electrodeposited nanocrystalline Ag coating. Microstructural features were investigated with transmission electron microscopy (TEM). The results indicate that the addition of Bi introduced nanometer-scale Ag-Bi solid solution particles and more internal defects to the initial Ag microstructures. The anisotropic elastic-plastic properties of the Ag nanocrystalline coating with and without Bi addition were examined with nanoindentation experiments in conjunction with the recently-developed inverse method. The results indicate that the as-deposited nanocrystalline Ag coating contained high mechanical anisotropy. With the addition of 1 atomicmore » percent (at%) Bi, the anisotropy within Ag-Bi coating was very small, and yield strength of the nanocrystalline Ag-Bi alloy in both longitudinal and transverse directions were improved by over 100% compared to that of Ag. On the other hand, the strain-hardening exponent of Ag-Bi was reduced to 0.055 from the original 0.16 of the Ag coating. Furthermore, the addition of Bi only slightly increased the electrical resistivity of the Ag-Bi coating in comparison to Ag. Lastly, results of our study indicate that Bi addition is a promising method for improving the mechanical and physical performances of Ag coating for electrical contacts.« less
  • Fine 3Y-ZrO{sub 2} added MoSi{sub 2}-based composites were fabricated by the conventional hot-pressing method. These composites mainly consisted of matrix MoSi{sub 2}, well-crystallized ZrSiO{sub 4}, Mo{sub {<=}5}Si{sub 3}C{sub {<=}1} and non-reacted tetragonal ZrO{sub 2}. The intergranular glassy SiO{sub 2} phase could be changed into the thermodynamically stable ZrSiO{sub 4} crystalline phase by the 3Y-ZrO{sub 2} addition. Mechanical properties at room temperature such as fracture toughness and strength were enhanced by the 3Y-ZrO{sub 2} addition. The enhancement of fracture toughness in the MoSi{sub 2}-3Y-ZrO{sub 2} system was attributed mainly to the decrease of the brittle glassy SiO{sub 2} phase at grainmore » boundaries and the residual compressive stresses induced by the mismatch of thermal expansion coefficient between MoSi{sub 2} and ZrSiO{sub 4}. These results indicate that in-situ crystallization of the glassy SiO 2 phase by the addition of 3Y-ZrO{sub 2} has great advantage to fabricate MoSi{sub 2}-based composites with well-balanced mechanical properties. Further optimization of fabrication conditions will enable one to improve the mechanical properties of MoSi{sub 2}-ZrO{sub 2} system.« less
  • Ti and Ti alloys are widely used in restorative surgery because of their good biocompatibility, enhanced mechanical behavior and high corrosion resistance in physiological media. The corrosion resistance of Ti-based materials is due to the spontaneous formation of the TiO{sub 2} oxide film on their surface, which exhibits elevated stability in biological fluids. Ti–Nb alloys, depending on the composition and the processing routes to which the alloys are subjected, have high mechanical strength combined with low elastic modulus. The addition of Sn to Ti–Nb alloys allows the phase transformations to be controlled, particularly the precipitation of ω phase. The aimmore » of this study is to discuss the microstructure, mechanical properties and corrosion behavior of cast Ti–Nb alloys to which Sn has been added. Samples were centrifugally cast in a copper mold, and the microstructure was characterized using optical microscopy, scanning electron microscopy and X-ray diffractometry. Mechanical behavior evaluation was performed using Berkovich nanoindentation, Vickers hardness and compression tests. The corrosion behavior was evaluated in Ringer's solution at room temperature using electrochemical techniques. The results obtained suggested that the physical, mechanical and chemical behaviors of the Ti–Nb–Sn alloys are directly dependent on the Sn content. - Graphical abstract: Effects of Sn addition to the Ti–30Nb alloy on the elastic modulus. - Highlights: • Sn addition causes reduction of the ω phase precipitation. • Minimum Vickers hardness and elastic modulus occurred for 6 wt.% Sn content. • Addition of 6 wt.% Sn resulted in maximum ductility and minimum compression strength. • All Ti–30Nb–XSn (X = 0, 2, 4, 6, 8 and 10%) alloys are passive in Ringer's solution. • Highest corrosion resistance was observed for 6 wt.% Sn content.« less
  • Laser-clad composite coatings on the Ti6Al4V substrate were heat-treated at 700, 800, and 900 °C for 1 h. The effects of post-heat treatment on the microstructure, microhardness, and fracture toughness of the coatings were investigated by scanning electron microscopy, X-ray diffractometry, energy dispersive spectroscopy, and optical microscopy. The wear resistance of the coatings was evaluated under dry reciprocating sliding friction at room temperature. The coatings mainly comprised some coarse gray blocky (W,Ti)C particles accompanied by the fine white WC particles, a large number of black TiC cellular/dendrites, and the matrix composed of NiTi and Ni{sub 3}Ti; some unknown rich Ni-more » and Ti-rich particles with sizes ranging from 10 nm to 50 nm were precipitated and uniformly distributed in the Ni{sub 3}Ti phase to form a thin granular layer after heat treatment at 700 °C. The granular layer spread from the edge toward the center of the Ni{sub 3}Ti phase with increasing temperature. A large number of fine equiaxed Cr{sub 23}C{sub 6} particles with 0.2–0.5 μm sizes were observed around the edges of the NiTi supersaturated solid solution when the temperature was further increased to 900 °C. The microhardness and fracture toughness of the coatings were improved with increased temperature due to the dispersion-strengthening effect of the precipitates. Dominant wear mechanisms for all the coatings included abrasive and delamination wear. The post-heat treatment not only reduced wear volume and friction coefficient, but also decreased cracking susceptibility during sliding friction. Comparatively speaking, the heat-treated coating at 900 °C presented the most excellent wear resistance. - Highlights: • TiC + WC reinforced intermetallic compound matrix composite coatings were produced. • The formation mechanism of the reinforcements was analyzed. • Two precipitates were generated at elevated temperature. • Cracking susceptibility and microhardness of the coatings were improved. • Post-heat treatment enhances wear resistance of the coatings.« less