Chuming Liu

Microstructure and properties of Ni–B–TiO2 nano-composite coatings fabricated by electroless plating

Abstract Ni–B coatings are used in automotive, aerospace, petrochemical, and electronic industries due to their high hardness, good wear and corrosion resistance. In this research, nano-composite Ni–B–TiO2 coatings are deposited on mild steel samples by electroless plating method. A systematic study of Ni–B–xTiO2 coatings with different TiO2 concentrations (x = 0–20 g L−1) has been conducted. The coatings are characterised using SEM, XRD, microhardness and wear testers. It is found that the incorporation of TiO2 nano-powder can significantly improve the mechanical properties of Ni–B coatings. The microstructure and mechanical properties of the electroless deposited Ni–B–TiO2 nano-composite coatings is strongly affected by the amount of TiO2 addition. The correlation of the TiO2 concentrations with the microstructure and properties of coatings are discussed.

Manufacturing high-performance Mg alloy through hot extrusion

ABSTRACT Mg-Gd-Y-Zr alloy is usually manufactured through method of combined homogenization, hot deformation and aging treatment and the obtained alloy usually exhibits low ductility. In this investigation, Mg-Gd-Y-Zr alloy possessing superior overall mechanical properties, both high ductility and strength, was obtained through a method of hot extrusion applied on the as cast alloy and a following T6 treatment involving a short solution and an aging. The coarse grains in the as cast alloy was severely refined during the extrusion processing, accompanied with the decomposition and dissolving of the eutectic structure generated during casting. After T6-treated, the alloy exhibits superior comprehensive mechanical properties of 293 MPa in yield strength and 9.4% in elongation. Compared with the alloy processed by extrusion and T5 treatment, which is usually used for wrought magnesium alloy, this alloy exhibits an increment of more than 90% in ductility with a sacrifice as low as 2% in yield strength. Meanwhile, the fabrication process is notably shortened. The improvement in mechanical property is attributed to the random texture, generated in the extrusion without a foregoing homogenization. This manufacturing method of combining extrusion and T6 treatment throws light on the application of extruded magnesium alloy through the significant improvement in ductility, notable shortening in fabrication process procedure and the sever reduction in energy consumption.

Effect of Dy and Nd on ZK10 alloy processed by hot extrusion

ABSTRACT About 0.6%Dy and 0.2%Nd are simultaneously added to ZK10 alloy processed by hot extrusion, and their effects are investigated. Obvious refined grains and weakened texture are observed after addition of Dy and Nd. Significantly improved mechanical performance with increase of 16% in yield strength and of 114% in ductility is obtained compared with ZK10 alloy. The strengthening effect is attributed to the grain refinement and solid solution, and the enhanced ductility results from the refined structure and weakened texture. Better optimization in mechanical performance with enhanced strengthening is generated, compared with the alloy with individual RE element addition. Combined addition of trace Dy and Nd throws light on the wide-range production and application of extruded ZK10 alloy.

Correction to: Effects of Changing Hot Rolling Direction on Microstructure, Texture and Mechanical Properties of Cu-2.7Be Sheets

Please note that an affiliation for all authors of this article was incorrectly given as “School of Materials Science and Technology, Central South University, Changsha, China”

Effects of Changing Hot Rolling Direction on Microstructure, Texture and Mechanical Properties of Cu-2.7Be Sheets

A hot rolling scheme (cross-rolling and unidirectional rolling) was adopted to process Cu-2.7Be sheets used as multiplier dynodes in photomultiplier. The effects of changing rolling direction on microstructure, texture and mechanical properties were studied by a combination of XRD, EBSD and TEM. It was found that higher copper-type texture and lower brass texture intensity were obtained in the ultimately cross-rolling (CR) sheet compared with the unidirectional rolling (UR) sheet.The EBSD results indicated that the grain orientation from mainly

Double-layered Ni-P/Ni-P-ZrO2 electroless coatings on AZ31 magnesium alloy with improved corrosion resistance

\left\langle {101} \right\rangle

Duplex Ni–P–ZrO2/Ni–P electroless coating on stainless steel

101 for UR sample turns to random for CR sample. Great enhancements in YS and UTS after unidirectional rolling were attributed to the massive and polygonal γ precipitates. The CR sample exhibited lower anisotropy, because of the increase of S and γ precipitates with spherical and tiny shape.