Interfacial microstructure and shear strength of Ti-6Al-4V/TiAl laminate composite sheet fabricated by hot packed rolling

A two layer Ti-6Al-4V(wt%)/Ti-43Al-9V-Y(at%) laminate composite sheet with a uniform interfacial microstructure and no discernible defects at the interfaces has been prepared by hot-pack rolling, and its interfacial microstructure and shear strength were characterized. Characterization of the interfacial microstructure shows that there was an interfacial region of uniform thickness of about 250 μm which consisted of two layers: Layer I on the TiAl side which was 80 μm thick and Layer II on the Ti-6Al-4V side which was 170 μm thick. The microstructure of Layer I consisted of massive γ phases, needlelike γ phases and B2 phase matrix, while the microstructure of Layer II consisted of α₂ phase. The microstructure of the interfacial region is the result of the interdiffusion of Ti element from Ti-6Al-4V alloy layer into the TiAl alloy layer and Al element from the TiAl alloy layer into the Ti-6Al-4V alloy layer. The shear strength measurement demonstrated that the bonding strength between the TiAl alloy and Ti-6Al-4V alloy layers in the laminate composite sheet was very high. This means that the quality of the interfacial bonding between the two layers achieved by the multi-path rolling is high, and the interface between the layers is very effective in transferring loading, causing significantly improved toughness and plasticity of the TiAl/Ti-6Al-4V laminate composite sheet

Microstructure and mechanical properties of large size as-cast Ti-43Al-9V-0.2Y (at.%) alloy ingot from brim to centre

A Ti-43Al-9V-0.2Y (at.%) alloy ingot with the size of Ф160×400mm was prepared by vacuum arc remelting (VAR). The microstructure of the as-cast Ti-43Al-9V-0.2Y alloy was composed of B2/α₂/γ lamellar colonies and massive B2 and γ phases which were distributed along the boundaries of these lamellar colonies in the form of equiaxed grains. Based on the grain size variation along the radius direction of the ingot, the ingot could be divided into four ring regions from brim to centre. It has been understood that the grain size variation between these four regions was due to the interplay of the effects of the cooling rate and the yttrium content on solidified microstructures in these regions. Mechanical testing of the samples cut from these four regions showed that there existed a clear correlation between the yield strength and the average grain sizes of the four ring regions, which approximately conformed to a Hall-Petch relationship

Propagation Analysis of 2.4 GHz Wireless Sensor Network Signal in a Plantation

Wireless sensor network is a popular technology on information acquisition and processing, which has been widely used in plantation ecological monitoring domain. The plantation environments, including antenna height-gain, depolarization, terrain, humidity and many factors have great influences on the propagation of 2.4GHz wireless sensor network radio frequency signal. In this paper, a complete research for propagation law of 2.4GHz wireless sensor network signal in plantation environment is presented, with using regression of support vector machines based on experimental data. A single variable prediction model is established on field strength of wireless sensor network signal in plantation environment, thus compares it with the original experience prediction model and measured data. The establishment of aforesaid model provides an important theoretical support for determining the max effective communication range of wireless sensor node and the nodes' rational distribution. It will certainly promote the application of wireless sensor network in plantation ecological monitoring field

Genome-wide analysis of Dongxiang wild rice (Oryza rufipogon Griff.) to investigate lost/acquired genes during rice domestication

This file reports the functional annotation of 99,092 DXWR transcripts from the NCBI NR database using the software blast2go. This file is in the tab delimited format and can be opened using the software Excel. (TXT 12649 kb

High temperature deformation behavior of Ti–46Al–2Cr–4Nb–0.2Y alloy

The hot deformation characteristics of cast and hot isostatically pressed Ti-46Al-2Cr-4Nb-0.2Y (at%) alloy in the temperature range of 1100-1250°C and strain rate range of 0.01-1.0s -1 using hot compression tests were studied. The processing map of the alloy at true strain of 0.5 was also developed on the basis of the dynamic materials model (DMM). The experimental results show that the flow stress decreases significantly with increasing deformation temperature and decreasing strain rate. Using the kinetic rate equation the stress exponent n and the apparent activation energy of deformation Q were determined as 4.47 and 400.4kJmol -1, respectively. The efficiency values of power dissipation of the domain at strain rate below 0.4s -1 show that the dynamic recrystallization occurring of γ phase in the alloy is easier in the wide deformation temperature range (1100-1250°C) due to low stacking fault energy. The fraction of new recrystallized grains increased with increasing the hot deformation temperature at a given strain rate. With the increasing of strain rate, the uniformity of microstructure was decreased. The domain defined by the temperature range of 1200-1230°C and the strain rate range of 0.01-0.05s -1 which corresponds to a peak efficiency of about 60% is the optimal deformation condition of the alloy. Based on the optimal deformation conditions, a cylindrical sample was near isothermally forged. The microstructure and shape of pancake by forging was in good agreement with the prediction of processing map

Polysulfide nanoparticles-reduced graphene oxide composite aerogel for efficient solar-driven water purification

Along with the environmental pollution, the scarcity of clean water seriously threatens the sustainable development of human society. Recently, the rapid development of solar evaporators has injected new vitality into the field of water purification. However, the industry faces a considerable challenge of achieving comprehensive purification of ions, especially the efficient removal of mercury ions. In this work, we introduce an ideal mercury-removal platform based on facilely and cost-effectively synthesized polysulfide nanoparticles (PSNs). Further development of PSN-functionalized reduced graphene oxide (PSN-rGO) aerogel evaporator results in achieving a high evaporation rate of 1.55 kg m−2 h−1 with energy efficiency of 90.8% under 1 sun. With the merits of interconnected porous structure and adsorption ability, the photothermal aerogel presents overall purification of heavy metal ions from wastewater. During solar desalination, salt ions can be rejected with long-term stability. Compared with traditional water purification technologies, this highly efficient solar evaporator provides a new practical method to utilize clean energy for clean water production

Microstructure and mechanical properties of TiAl alloys produced by rapid heating and open die forging of blended elemental powder compacts

Ti-43Al-5V-4Nb (at%) intermetallic compounds were fabricated by a rapid heating and open die forging method using blended elemental powders. The process route consisted of powder blending, compacting, rapid heating, open die forging and heat treatment. During heating there is porosity in the blended and warm compacted powder billets which still persists after the first forging. In order to remove this difficulty a two stage forging process was used. A fully lamellar structure was seen in the TiAl alloy after heat treatment. Overall, the TiAl alloy showed moderately good mechanical properties at room temperature and good mechanical properties, with reasonable strength and good ductility at high temperatures