Microstructure, mechanical properties, and deformation behavior of Sn–1.0Ag–0.5Cu solder after Ni and Sb additions

The ability to map plastic deformation around high strain gradient microstructural features is central in studying phenomena such as fatigue and stress corrosion cracking. A method for the visualization of plastic deformation in electron back-scattered diffraction (EBSD) data has been developed and is described in this article. This technique is based on mapping the intragrain misorientation in polycrystalline metals. The algorithm maps the scalar misorientation between a local minimum misorientation reference pixel and every other pixel within an individual grain. A map around the corner of a Vickers indentation in 304 stainless steel was used as a test case. Several algorithms for EBSD mapping were then applied to the deformation distributions around air fatigue and stress corrosion cracks in 304 stainless steel. Using this technique, clear visualization of a deformation zone around high strain gradient microstructural features (crack tips, indentations, etc.) is possible with standard EBSD data.

Misorientation mapping for visualization of plastic deformation via electron back-scattered diffraction.

Nitrogen fixation is the second most important chemical process in nature next to photosynthesis. Herein, we report a novel g-C3N4/ZnSnCdS heterojunction photocatalyst prepared using the hydrothermal method that has an outstanding nitrogen photofixation ability under visible light. The as-prepared ZnSnCdS is the ternary metal sulfide Zn0.11Sn0.12Cd0.88S1.12 with many sulfur vacancies, not a mixture of ZnS, SnS2, and CdS. Strong electronic coupling, as evidenced by the ultraviolet–visible, X-ray photoelectron spectroscopy, photoluminescence, and electrochemical impedance spectra results, exists between two components in the g-C3N4/ZnSnCdS heterojunction photocatalysts, leading to more effective separation of photogenerated electron–hole pairs and faster interfacial charge transfer. The sulfur vacancies on ternary metal sulfide not only serve as active sites to adsorb and activate N2 molecules but also promote interfacial charge transfer from ZnSnCdS to N2 molecules, thus significantly improving the nitroge...

Construction of g-C3N4/Zn0.11Sn0.12Cd0.88S1.12 Hybrid Heterojunction Catalyst with Outstanding Nitrogen Photofixation Performance Induced by Sulfur Vacancies

Artificial rabbits optimization: A new bio-inspired meta-heuristic algorithm for solving engineering optimization problems

Evolution of microstructure, thermal and creep properties of Ni-doped Sn–0.5Ag–0.7Cu low-Ag solder alloys for electronic applications

Revisiting mechanisms to inhibit Ag3Sn plates in Sn-Ag-Cu solders with 1 wt.% Zn addition

Ultrasonic characterization of thermally grown oxide in thermal barrier coating by reflection coefficient amplitude spectrum.

Ultrasonic characterization of thermal barrier coatings porosity through BP neural network optimizing Gaussian process regression algorithm.

Aim at nondestructively characterizing the interfacial roughness of coatings, ultrasonic reflection coefficient phase spectrum (URCPS) as a function of interfacial roughness is derived based on the phase screen approximation theory [ 1 ]. For inhomogeneous coatings, the attenuation coefficient α(f) shows a non-negligible effect on the URCPS. The relationship of α(f) on frequency f is used to decouple the URCPS. The constructed URCPS is used to determine the interfacial roughness and thickness of specimens through a two-parameter inversion utilizing the cross-correlation algorithm. The effects of the coating inhomogeneity (such as porosity) on the roughness measurement are analyzed through numerical calculation. A series of simulations with interfacial roughness from 6.2 to 12.7 μm indicate that measurement errors of the thickness are all less than 8.0%. The relative errors of the measured roughness of models without porosity and models with the porosity of 3% are less than 11.8%. For the models with porosity 5%, when the roughness is larger than 10.3 μm, the relative error is still larger than 11.7%. Ultrasonic experiments were carried out on a tungsten carbide (WC Ni) coating utilizing water immersion, flat transducer. The WC-Ni coating, with unknown interfacial roughness, was sprayed on a stainless steel using the high-velocity oxygen fuel (HVOF) method. Experimental results show that the interfacial roughness of specimen obtained by the proposed ultrasonic measurement are in good agreement with that of SEM observations, the absolute error of the measured roughness is less than 1.4 μm and the relative error was less than 11.0%.

Quantitative characterization of the interfacial roughness and thickness of inhomogeneous coatings based on ultrasonic reflection coefficient phase spectrum

Precise knowledge of ultrasonic travel time in carbon fiber reinforced plastics (CFRP) is difficult to obtain due to the layered anisotropic nature. This paper proposes a model-based method to calculate the travel time of qP wave in CFRP laminates. The aim is to correct the time delays of total focusing method (TFM) applied to post-process the full matrix capture data for enhanced ultrasonic imaging. Experiments show that a 4.84 mm delamination is accurately sized by corrected TFM. The associated detection sensitivity is 46.0 dB and 3.6 dB above those of paintbrush acquisition and basic TFM, respectively.

Zhongbing Luo

Papers

Revisiting mechanisms to inhibit Ag3Sn plates in Sn-Ag-Cu solders with 1 wt.% Zn addition

Ultrasonic characterization of thermally grown oxide in thermal barrier coating by reflection coefficient amplitude spectrum.

Ultrasonic characterization of thermal barrier coatings porosity through BP neural network optimizing Gaussian process regression algorithm.

Quantitative characterization of the interfacial roughness and thickness of inhomogeneous coatings based on ultrasonic reflection coefficient phase spectrum

Total focusing method imaging of multidirectional CFRP laminate with model-based time delay correction