Chaofang Dong

Bio: Chaofang Dong is an academic researcher from University of Science and Technology Beijing. The author has contributed to research in topics: Corrosion & Materials science. The author has an hindex of 39, co-authored 249 publications receiving 5684 citations. Previous affiliations of Chaofang Dong include University of Calgary & Chinese Ministry of Education.

Materials science: Share corrosion data.

Abstract: To prevent disasters, Xiaogang Li and colleagues call for open data infrastructures to collate information on materials failures.

The electrochemical behaviour of 2205 duplex stainless steel in alkaline solutions with different pH in the presence of chloride

Abstract: The electrochemical behaviour of 2205 duplex stainless steel in alkaline solutions with different pH values in the presence of NaCl was evaluated by different techniques: potentiodynamic measurements, electrochemical impedance spectroscopy and capacitance measurements (Mott–Schottky approach). The chemical composition was studied by X-ray photoelectron spectroscopy (XPS). In addition, the site of pitting nucleated preferentially on the duplex stainless steel had been confirmed by scanning electron microscopy (SEM). The results indicated that both the pH and immersion time play important roles in the evolution of the film resistance, charge transfer processes and the occurrence of pitting. The composition of the surface film changes with the pH value. The film formed in the alkaline solution, presenting a bilayer structure, predominantly contained Fe species and Cr-oxide. The NH 3 /NH 4 + species in the passive film are disappeared in the pH 10.5 solution. The pit initiation sites occurred in austenite phase near the γ/δ boundaries or at inclusions. The number and size of the pits increases with the decrease of pH value after long time immersion.

Passivity of 316L stainless steel in borate buffer solution studied by Mott-Schottky analysis, atomic absorption spectrometry and X-ray photoelectron spectroscopy

Abstract: The passivity of 316L stainless steel in borate buffer solution has been investigated by Mott–Schottky, atomic absorption spectrometry (AAS) and X-ray photoelectron spectroscopy (XPS). The results indicate that the polarization curve in the passive region possesses several turning potentials (0 VSCE, 0.2 VSCE, 0.4 VSCE, 0.6 VSCE and 0.85 VSCE). The passive films formed at turning potentials perform different electrochemical and semiconductor properties. Further, the compositions of the passive films formed at turning potentials are investigated. The results reasonably explain why these potentials appear in the passive region and why specimens perform different properties at turning potentials.

Effects of hydrogen-charging on the susceptibility of X100 pipeline steel to hydrogen-induced cracking

Abstract: In this work, the hydrogen-induced cracking (HIC) behavior of X100 pipeline steel was investigated by a combination of tensile test, electrochemical hydrogen permeation measurement and surface characterization techniques. The effect of inclusions in the steel on the crack initiation was analyzed. Results demonstrated that the amount of hydrogen-charging into the X100 steel specimen increases with the charging time and charging current density. Hydrogen-charging will enhance the susceptibility of the steel to HIC. The cracks initiate primarily at inclusions, such as aluminum oxides, titanium oxides and ferric carbides, in the steel. The diffusivity of hydrogen at room temperature in X100 steel is determined to be 1.04 × 10−8 cm2/s.

Mechanical properties and corrosion behavior of selective laser melted 316L stainless steel after different heat treatment processes

Abstract: Irregular grains, high interfacial stresses and anisotropic properties widely exist in 3D-printed metallic materials, and this paper investigated the effects of heat treatment on the microstructural, mechanical and corrosion properties of 316 L stainless steel fabricated by selective laser melting. Sub-grains and low-angle boundaries exist in the as-received selective laser melted (SLMed) 316 L stainless steel. After heat treatment at 1050 °C, the sub-grains and low-angle boundaries changed slightly, and the stress state and strength decreased to some extent due to the decrease of dislocation density. After heat treatment at 1200 °C, the grains became uniform, and the dislocation cells vanished, which led to a sharp decline in the hardness and strength. However, the ductility was improved after recrystallization heat treatment. The passive film thickness and corrosion potential of the SLMed 316 L stainless steel decreased after heat treatment, and the pitting potential also decreased due to the accelerated transition from metastable to steady-state pitting; this accelerated transition was caused by the presence of weak passive films at the enlarged pores after heat treatment, especially for an adequate solid solution treatment.

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fundamentals and advances in magnesium alloy corrosion

Abstract: There remains growing interest in magnesium (Mg) and its alloys, as they are the lightest structural metallic materials Mg alloys have the potential to enable design of lighter engineered systems, including positive implications for reduced energy consumption Furthermore, Mg alloys are also emerging as viable biodegradable materials and battery electrodes In spite of the greatest historical Mg usage at present, the wider use of Mg alloys remains restricted by a number of inherent limitations, including vulnerability to corrosion, poor formability and low creep resistance This review covers recent research that has led to advances in Mg-alloy corrosion; including the application of contemporary methods for understanding Mg corrosion, the establishment of an electrochemical framework for Mg corrosion, illumination of alloying effects, and attempts at corrosion resistant Mg alloys A discussion drawing from many sources provides an unbiased focus on new achievements, as well as some contentious issues in the field The electrochemistry of Mg is reviewed in detail, including so-called anodic hydrogen evolution and cathodic activation This review also covers atmospheric corrosion, and biodegradable Mg alloys Finally, past and present trends in the field of Mg corrosion are reviewed, identifying knowledge gaps, whilst attempting to also identify future developments and directions