Jiankang Huang

Bio: Jiankang Huang is an academic researcher from Lanzhou University of Technology. The author has contributed to research in topics: Welding & Gas metal arc welding. The author has an hindex of 6, co-authored 35 publications receiving 160 citations.

Corrosion Behavior of Aluminum-Steel Weld-Brazing Joint

Abstract: Dissimilar metals of 1060 aluminum and galvanized steel were joined with a lap joint by pulsed double-electrode gas metal arc weld brazing with aluminum-magnesium and aluminum-silicon filler metals. The corrosion behavior of the weld joints was investigated with immersion corrosion and electrochemical corrosion tests, and the corrosion morphology of the joints was analyzed with scanning electron microscopy (SEM). Galvanic corrosion was found to occur when the samples were immersed in corrosive media, and the corrosion rate of joints was increased with increased heat input of the workpiece. Comparison of the corrosion properties of weld joints with different filler wires indicated that the corrosion rate of weld joints with aluminum-silicon filler wire was larger than that of weld joints with aluminum-magnesium filler wire. Results also showed that the zinc-rich zone of weld joints was prone to corrosion. The corrosion behavior of zinc-rich zone was analyzed with SEM equipped with an energy-dispersive x-ray spectroscopy analysis system based on the test results.

Analysis and modeling of the growth of intermetallic compounds in aluminum–steel joints

Abstract: In this work, we experimentally and numerically studied the microstructures and growth of intermetallic compounds (IMCs) formed in Al–Fe (aluminum–steel) joints welded by a pulsed double electrode gas metal arc welding (DE-GMAW)-brazing method. The IMCs consist of Fe2Al5 and FeAl3, with Fe2Al5 being the main compound in the joints. The thickness of an IMC layer increases with an increase of the welding current (heat input) into the base metal. EBSD measurement suggests that the preferred crystal orientation of the Fe2Al5 IMC likely provides the necessary path for Al atoms to migrate through the IMC layer for further growth of the Fe2Al5 IMC layer toward the steel substrate. The Monte Carlo method was used to simulate growth of the IMCs in the joints. Numerical results are in good accord with the experimental results, suggesting that Fe2Al5 IMC is first formed in the initial brazing interface between liquid Al and steel substrate, and then the interface between the liquid Al and steel substrate evolves into two new interfaces: one is an interface between the Fe2Al5 IMC layer and the steel substrate, and the other is an interface between the Fe2Al5 IMC layer and liquid Al. During growth of the Fe2Al5 IMC, FeAl3 IMC forms in the interface between the Fe2Al5 IMC layer and the Al and then grows into the Al. The thickness of the Fe2Al5 layer increases nonlinearly with an increase in the growth time.

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.

Friction stir welding of dissimilar aluminum alloys and steels: a review

Abstract: The present paper is focused on friction stir welding (FSW) of dissimilar aluminum alloys and steels, an area that is getting great concern recently The promise of FSW joints lies in low welding heat input and its ability to minimize the extent of the formation of intermetallic compound (IMC) in dissimilar metals The present paper assessed the status of FSW process of dissimilar aluminum alloys and steels, and to identify the opportunities and challenges for the future The essential reason for the formation of the dissimilar Al/steel FSW joints with high quality is explained by super diffusion behavior This paper will provide basis to designers and engineers to consider FSW for a wider range of dissimilar aluminum alloys and steels

A state-of-the-art review of the fabrication and characteristics of titanium and its alloys for biomedical applications.

Abstract: Commercially pure titanium and titanium alloys have been among the most commonly used materials for biomedical applications since the 1950s. Due to the excellent mechanical tribological properties, corrosion resistance, biocompatibility, and antibacterial properties of titanium, it is getting much attention as a biomaterial for implants. Furthermore, titanium promotes osseointegration without any additional adhesives by physically bonding with the living bone at the implant site. These properties are crucial for producing high-strength metallic alloys for biomedical applications. Titanium alloys are manufactured into the three types of α, β, and α + β. The scientific and clinical understanding of titanium and its potential applications, especially in the biomedical field, are still in the early stages. This review aims to establish a credible platform for the current and future roles of titanium in biomedicine. We first explore the developmental history of titanium. Then, we review the recent advancement of the utility of titanium in diverse biomedical areas, its functional properties, mechanisms of biocompatibility, host tissue responses, and various relevant antimicrobial strategies. Future research will be directed toward advanced manufacturing technologies, such as powder-based additive manufacturing, electron beam melting and laser melting deposition, as well as analyzing the effects of alloying elements on the biocompatibility, corrosion resistance, and mechanical properties of titanium. Moreover, the role of titania nanotubes in regenerative medicine and nanomedicine applications, such as localized drug delivery system, immunomodulatory agents, antibacterial agents, and hemocompatibility, is investigated, and the paper concludes with the future outlook of titanium alloys as biomaterials.

Relationship between intermetallic compound layer thickness with deviation and interfacial strength for dissimilar joints of aluminum alloy and stainless steel

Abstract: The relationship between the intermetallic compound (IMC) layer thickness including the deviation and joint strength was evaluated for the dissimilar joints between aluminum alloys and austenitic stainless steel. To evaluate the interface with various IMC layer thicknesses, the joints by friction stir welding were solution-heat-treated and artificially aged. The transitions of joint strength and fracture position were characterized for the IMC layer thickness ranging from 0 to 2.5 µm. Further, we demonstrated that the fracture position can be determined by the percentage of the joining area via the IMC layer thickness below a threshold value, which was 0.4 µm.