Showing papers by "Xiaojian Wang published in 2020"
TL;DR: In this article, three different topological porous structures (primitive, gyroid, bcc) with a porosity of 65% were designed and fabricated by selective laser melting using Ti-6Al-4V powders.
74 citations
TL;DR: In order to further improve the corrosion resistance of commercial pure titanium (CP-Ti), the ex-situ formed Ti-5 wt.% TiN composite was developed by selective laser melting (SLM) and the corrosion behavior of the SLM-produced CP-Ti and Ti- 5 Wt.%.% composite in 0.5 M HCl solution was investigated as mentioned in this paper.
40 citations
TL;DR: In this paper, a facile surface modification method to improve the tribological performances of selective laser melting (SLM) manufactured titanium parts was reported. But the surface texture was not considered.
25 citations
TL;DR: In this article, the effects of degradation environment on the in vitro stress corrosion cracking (SCC) behavior of biomedical Mg-1Zn alloy were investigated and the resistance to SCC initiation and propagation for Mg alloy in synthetic cell culture medium and natural bovine calf serum (BCS) were improved compared to phosphate-buffered saline (PBS) and modified simulated body fluid (m-SBF).
23 citations
TL;DR: In this article, a phosphorylcholine chitosan (PCCs) coating was applied to a bionic cell membrane surface, using a silane conversion layer (APTE) as the connection layer.
23 citations
TL;DR: 2D nanomaterials possess fascinating properties and are found in multifarious devices and applications including energy storage devices, new generation of battery technologies, sensor devices, and more recently in biomedical applications.
Abstract: 2D nanomaterials (2DNMs) possess fascinating properties and are found in multifarious devices and applications including energy storage devices, new generation of battery technologies, sensor devices, and more recently in biomedical applications. Their use in biomedical applications such as tissue engineering, photothermal therapy, neural regeneration, and drug delivery has opened new horizons in treatment of age-old ailments. It is also a rapidly developing area of advanced research. A new approach of integrating 3D printing (3DP), a layer-by-layer deposition technique for building structures, along with 2DNM multifunctional inks, has gained considerable attention in recent times, especially in biomedical applications. With the ever-growing demand in healthcare industry for novel, efficient, and rapid technologies for therapeutic treatment methods, 3DP structures of 2DNMs provide vast scope for evolution of a new generation of biomedical devices. Recent advances in 3DP structures of dispersed 2DNM inks with established high-performance biomedical properties are focused on. The advantages of their 3D structures, the sustainable formulation methods of such inks, and their feasible printing methods are also covered. Subsequently, it deals with the therapeutic applications of some already researched 3DP structures of 2DNMs and concludes with highlighting the challenges as well as the future directions of research in this area.
17 citations
TL;DR: The results showed that as SLM samples were mainly composed of needle-like α′ martensite, heat treatment caused α′ phase to decompose, forming a lamellar α+β mixed microstructure, and heat treatment improved the energy absorption efficiency of the porous Ti64.
Abstract: In this work, Ti-6Al-4V (Ti64) porous structures were prepared by selective laser melting (SLM), and the effects of post heat treatment on its microstructural and mechanical properties were investigated. The results showed that as SLM samples were mainly composed of needle-like α' martensite. Heat treatment at 750 °C caused α' phase to decompose, forming a lamellar α+β mixed microstructure. As the heat treatment temperature increased to 950 °C, the width of lamellar α phase gradually increased to 3.1 μm. Heat treatment also reduced the compressive strength of the samples; however, it significantly improved the ductility of the porous Ti64. Moreover, heat treatment improved the energy absorption efficiency of the porous Ti64. The samples heat-treated at 750 °C had the highest energy absorption of 233.6 ± 1.5 MJ/m3 at e = 50%.
16 citations
TL;DR: In this paper, phytic acid (PA), branched polyethylenimine (bPEI), and graphene oxide (GO) were introduced onto Mg 1Zn alloy via layer-by-layer assembly technique.
Abstract: Magnesium (Mg) alloys have shown great potential for biomedical implant materials due to their biodegradability and suitable mechanical strength. Recent works have shown that biomedical Mg alloys suffered from accelerated degradation rates when exposed to a stressed condition in biological media. Therefore, it is necessary to endow Mg alloys with enhanced stress corrosion cracking resistance. In this study, phytic acid (PA), branched polyethylenimine (bPEI) and graphene oxide (GO) were introduced onto Mg 1Zn alloy via layer-by-layer (LbL) assembly technique. The characteristics of the multilayer films were investigated by SEM, FTIR and XPS. Biodegradability Corrosion resistance of the samples was measured by electrochemical and immersion tests. The stress corrosion cracking (SCC) behaviour of the LbL coated Mg alloys was performed using slow strain rate tensile (SSRT) tests. The results showed that the multilayer coating with smooth and uniform morphologies could enhance the corrosion resistance of Mg alloys due to the physical barrier. The LbL coating exhibited a remarkable ability to improve the SCC resistance of Mg 1Zn alloy in Dulbecco's modified eagle medium.
14 citations
TL;DR: In this paper, Zn1Mg alloy was used as the base alloy with adding varied amounts of zirconium (Zr), and both casting and extrusion were employed to treat the developed alloys.
14 citations
TL;DR: The electrochemical impedance spectroscopy (EIS) results showed that the PCCs layer remarkably increased the resistance against corrosion attack, protecting substrates from over-quick degradation, and the protective effect of the layer with a thickness of 200 nm lasts for about 24 h.
Abstract: Zinc (Zn) alloys are promising alternatives to magnesium (Mg)- and iron (Fe)-based alloys because of their moderate corrosion rate and superior biocompatibility. To reduce the mass release of Zn2+ and improve the biocompatibility of Zn implants, the biomimetic zwitterionic polymer layer (phosphorylcholine chitosan-PCCs) was immobilized on the plasma-treated Zn1Mg surface. It is the chemical bonds between the -NH2 groups of the PCCs chain and O-C═O (C═O) groups on the plasma-treated Zn1Mg (Zn1Mg-PP) that contributes to the strong bonding strength between the film and the substrate, by which the PCCs (approx. 200 nm thick) layer can bear a 5.93 N normal load. The electrochemical impedance spectroscopy (EIS) results showed that the PCCs layer remarkably increased the resistance against corrosion attack, protecting substrates from over-quick degradation, and the protective effect of the layer with a thickness of 200 nm lasts for about 24 h. The corrosion products of Zn1Mg-PP-PCC in NaCl solution were determined as Zn5(OH)8Cl2·H2O and Zn3(PO4)2. Besides, the bulk Zn1Mg can trigger more aggressive macrophage activity, while the surface of Zn1Mg-PP and Zn1Mg-PP-PCC and their corrosion products (Zn3(PO4)2) tend to promote the differentiation of macrophages into the M2 phenotype, which is beneficial for implant applications.
11 citations
17 Apr 2020
TL;DR: In this article, a near β titanium alloy, Ti5Al2Sn2Zr4Mo4Cr, was fabricated by directed energy deposition (DED) with different powder feed rates to investigate the formation of fully equiaxed β grains.
Abstract: A near β titanium alloy, Ti5Al2Sn2Zr4Mo4Cr, was fabricated by directed energy deposition (DED) with different powder feed rates to investigate the formation of fully equiaxed β grains. A two-dimensional numerical model was developed to investigate the thermal conditions of the molten pool. Experimental results showed that the formation of an epitaxial cellular structure at the bottom of the molten pool is almost unavoidable. An increase in the powder feed rate produces a moderate thermal condition and promotes the formation of equiaxed grains in a single cladding layer. However, it could not guarantee the formation of a fully equiaxed microstructure in a block sample. From a low to high powder feed rate, fully columnar, mixed equiaxed–columnar, and fully equiaxed microstructures were obtained. Grain morphology was also affected by the remolten process. Increasing the powder feed rate reduced the remolten depth and broke the continuity of the epitaxial cellular structure, leading to different grain morphologies.