Jingen Zhou

Effect of Ta content on martensitic transformation behavior of RuTa ultrahigh temperature shape memory alloys

Abstract Effects of Ta content on martensitic transformation (MT) behavior of Ru 100− x Ta x ( x =46–54 at.%) alloys have been investigated by differential scanning calorimetry, dilatometry, X-ray diffraction and optical microscopy. Ta content significantly affects the MT behavior of RuTa alloys. The one-stage reservible MT occurs in Ta-poor RuTa alloys with Ta content less than 49 at.%. The two-stage reservible MT takes place in near-equiatomic RuTa alloys. No reservible MT is observed in Ta-rich alloys with Ta content more then 52 at.% Ta. The MT temperatures and hysteresis of RuTa alloys decrease with increasing Ta content. The aged and thermal cycled processes are nearly no effect on the MT behavior of these alloys. The deforming way of RuTa alloys is twinning. The Ru 50 Ta 50 alloy is of the most excellent MT behavior among these RuTa alloys.

Metallographic Characterization of Porosity in A Cast Aluminum Alloy A356-T6

Microporosity in both HIPped and non-HIPped unmodified aluminum cast alloy A356-T6 was quantified metallographically in terms of its area, area percentage, length, sphericity and perimeter. In the studied materials, the secondary dendrite arm spacing (SDAS) values vary from 82μm to 96μm for both the HIPped and the non-HIPped castings. HIPping process significantly reduces porosity area fraction and pore sizes. The maximum area fraction of porosity and maximum pore area of the non-HIPped specimens are increased with increasing SDAS.

Phase Transformation of Cu-Mo-C Powder during Mechanical Alloying and Annealing Process

The allotropes of graphite and activated carbon were mixed with Cu and Mo powder, respectively. And the two groups of mixtures were high-energy milled and annealed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and DSC/TG were used to investigate the phase transformation during the milling and sintering process. For both groups of powder milled, Mo was hard to dissolve in Cu, and C mainly congregated in the surface of Cu powder. When Cu-Mo-graphite powder as milled was annealed, Mo2C was formed. In comparison to Cu-Mo-graphite alloyed powder, Cu-Mo-activated carbon powder partially formed Cu oxide and Mo oxide with higher binding energy during milling process, which caused higher reduction temperature of Cu oxide and reaction temperature of Mo2C.This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Study On Nano-Structured SnO2-23wt%TiO2-21wt%RuO2 Coated Titanium Anode

Sn is one of the most important elements for the Cl2-evolving anode coatings, but it always used as a minor additive. In this paper, an Sn-based ternary oxide coating with its composition of SnO2-23wt%TiO2-21wt%RuO2 was prepared by a sol-gel technique through etching, painting, sintering and annealing. The differential thermal analysis (DTA) shows that the crystallization behavior of the ternary xerogel is more similar to that of pure xerogels SnO2. X-rays diffraction (XRD) indicates that the coating is composed of rutile phase (Sn,Ti,Ru)O2. Any other undesired phases, for example, anatase TiO2 and metallic ruthenium phases are not found in the coatings. The microstructure and the morphologies were studied by a transmission electron microscope (TEM) and a scanning electron microscope (SEM). The results of energy dispersive spectrometer (EDS) indicate Sn content in the coatings remain at high level and coincident with the nominal composition. The grain sizes in the coatings are around 4 nm. The voltage of Cl2-evolution and O2-evolution shows the ternary coating has good electrochemical properties.