Effect of Heat Treatment on Impact Properties of TC10 Titanium Alloy

The impact properties of TC10 treated with different solid solution temperature were tested. The microstructure change and fracture morphology were observed. The effect of solution temperature on the impact properties of TC10 titanium alloy was studied. The results show that with the increase of solution temperature, the primary alpha phase decreases, when the temperature reached 950 degrees, all of the primary alpha phase changed into the beta phase. From the fracture appearance, the specimen changes from ductile fracture to brittle fracture, impact properties change with the temperature increased first and then decreased, appeared in the middle of a stable maximum value.

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Study on impact properties of Ti6211 titanium alloy at different temperatures

MATEC Web of Conferences ◽

10.1051/matecconf/202032111033 ◽

2020 ◽

Vol 321 ◽

pp. 11033

Author(s):

Yanwen Tian ◽

Fang Hao ◽

Enen Xu ◽

Junqi Du

Keyword(s):

Titanium Alloy ◽

Transition Temperature ◽

Impact Energy ◽

Fracture Morphology ◽

Impact Properties ◽

Brittle Transition ◽

Pendulum Test ◽

Different Temperatures ◽

Brittle Transition Temperature ◽

The Impact

In this paper, Charpy notched pendulum test was used to study the impact properties of Ti6211 titanium alloy at -60 ℃, -40 ℃, -20 ℃, 23 ℃, 100 ℃, 200 ℃ and 300 ℃, respectively, and the fracture morphology was analyzed. The ductile and brittle transition temperature of the material was deduced from the area of the radiation zone. The results show that with the increase of temperature, the impact energy of the alloy increases continuously, and when the temperature reaches above 0 ℃, the impact energy increases obviously, and the area of the radiative area of the fracture surface increases gradually. Which can be inferred that the ductile and brittle transition temperature of the alloy is about 50 ℃.

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Melt Crystallization of Nanocomposites of Poly(Vinylidene Fluoride) with OMS

MRS Proceedings ◽

10.1557/proc-0949-c03-05 ◽

2006 ◽

Vol 949 ◽

Cited By ~ 2

Author(s):

Bedriye Seyhan Ince-Gunduz ◽

Debeshu Amare ◽

Robert Alpern ◽

Peggy Cebe ◽

Jennifer Crawford ◽

...

Keyword(s):

Growth Rate ◽

Melting Point ◽

Optical Microscopy ◽

Vinylidene Fluoride ◽

Crystallinity Index ◽

Beta Phase ◽

Alpha Phase ◽

Melt Crystallization ◽

Poly Vinylidene Fluoride ◽

The Impact

ABSTRACTIn our previous work [1] we investigated the impact of cold-crystallization on the structure of nanocomposites of PVDF with Lucentite STN™ OMS and observed the crossover composition in which the crystallographic beta phase dominated over alpha phase. Here, melt crystallization of PVDF/OMS nanocomposites was studied in the range of 0 to 1.0 wt% of OMS. In crystallization from melt, a decrease in crystallinity index occurs as a result of an increase in OMS. While beta phase fraction increased with an increase of OMS content in the range of interest, the amount of alpha crystals was found to be dominant even at high OMS compositions. At 1.0 wt% of OMS, beta crystals had reached at most 30% of the total crystallinity. Polarizing optical microscopy (POM) studies showed smaller, less birefringent spherulites with higher melting temperature compared to alpha spherulites appeared with OMS addition. Growth rate of these weakly birefringent spherulites is smaller than that of the strongly birefringent alpha spherulites. The increase in size and amount of the weakly birefringent spherulites with an increase of OMS and their higher melting point suggests these spherulites may be in the beta crystallographic phase.

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Investigation on the Effect of Low Temperature on Impact Properties of Ti-6Al-4V Titanium Alloy

10.21203/rs.3.rs-22904/v1 ◽

2020 ◽

Author(s):

wei zhao ◽

WenJia Su ◽

Liang Li ◽

Ding Fang ◽

Ni Chen

Keyword(s):

Titanium Alloy ◽

Low Temperature ◽

Low Temperatures ◽

Research Result ◽

Cutting Mechanism ◽

Impact Properties ◽

Fiber Area ◽

The Impact ◽

Cryogenic Cutting ◽

Radiation Area

Abstract Cryogenic cutting is becoming an attractive machining method for difficult-to-cut materials. However, it’s very difficult to analyze directly their cutting mechanism at low temperature. In order to better understand the various physical phenomena in the cryogenic cutting of titanium alloy, the Charpy impact test of Ti-6Al-4V titanium alloy at low temperatures (as low as -196 °C) was undertaken in this work. The Charpy absorbed energy of Ti-6Al-4V titanium alloy at low temperatures was investigated firstly. Then, by observing the microscopic and macroscopic morphology of the fracture, the impact properties and fracture modes of Ti-6Al-4V titanium alloy at low temperatures were analyzed. It was found that the impact toughness of Ti-6Al-4V titanium alloy reduces when the temperature decreases from 20 °C to -196 °C, and the fracture appears a tendency to become brittle. Meanwhile, three kinds of areas, i.e. shear lip area, fiber area, and radiation area, were found on the fracture morphology at each temperature. Those areas correspond to the shear fracture zone, crack initiation zone, and crack extension zone, respectively. With the decrease in temperature, the proportion of fiber area decreases, and the radiation area appears and increases gradually. However, fiber areas were still observed on the macroscopic morphology of the fracture under − 196 °C, which suggests that Ti-6Al-4V titanium alloy still has the ability to deform plastically at such low temperatures. The research result in this work provide a fundamental support for analyzing the cutting mechanism of Ti-6Al-4V titanium alloy at low temperatures.

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Land Subsidence Estimation for Aquifer Drainage Induced by Underground Mining

Energies ◽

10.3390/en14154658 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4658

Author(s):

Artur Guzy ◽

Wojciech T. Witkowski

Keyword(s):

Environmental Impact ◽

Land Subsidence ◽

Field Data ◽

Underground Mining ◽

Small Scale ◽

Aquifer System ◽

Maximum Value ◽

The Impact ◽

Method Model ◽

Impact Of Mining

Land subsidence caused by groundwater withdrawal induced by mining is a relatively unknown phenomenon. This is primarily due to the small scale of such movements compared to the land subsidence caused by deposit extraction. Nonetheless, the environmental impact of drainage-related land subsidence remains underestimated. The research was carried out in the “Bogdanka” coal mine in Poland. First, the historical impact of mining on land subsidence and groundwater head changes was investigated. The outcomes of these studies were used to construct the influence method model. With field data, our model was successfully calibrated and validated. Finally, it was used for land subsidence estimation for 2030. As per the findings, the field of mining exploitation has the greatest land subsidence. In 2014, the maximum value of the phenomenon was 0.313 cm. However, this value will reach 0.364 m by 2030. The spatial extent of land subsidence caused by mining-induced drainage extends up to 20 km beyond the mining area’s boundaries. The presented model provided land subsidence patterns without the need for a complex numerical subsidence model. As a result, the method presented can be effectively used for land subsidence regulation plans considering the impact of mining on the aquifer system.

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Effect of long-term moisture exposure on impact response of glass-reinforced vinylester

Proceedings of the Institution of Mechanical Engineers Part M Journal of Engineering for the Maritime Environment ◽

10.1177/1475090221996167 ◽

2021 ◽

pp. 147509022199616

Author(s):

Fatemeh Alizadeh ◽

Navid Kharghani ◽

Carlos Guedes Soares

Keyword(s):

Water Uptake ◽

Failure Modes ◽

Sea Water ◽

Composite Plates ◽

Impact Response ◽

Low Velocity Impact ◽

Water Type ◽

Interfacial Damage ◽

Impact Properties ◽

The Impact

Glass/Vinylester composite laminates are comprehensively characterised to assess its impact response behaviour under moisture exposure in marine structures. An instrumented drop weight impact machine is utilised to determine the impact responses of dry and immersed specimens in normal, salted and sea water. The specimens, which had three different thicknesses, were subjected to water exposure for a very long period of over 20 months before tested in a low-velocity impact experiment. Water uptake was measured primarily to study the degradation profiles of GRP laminates after being permeated by water. Matrix dissolution and interfacial damage observed on the laminates after prolonged moisture exposure while the absorption behaviour was found typically non-Fickian. The weight of the composite plates firstly increased because of water diffusion up to month 15 and then decreased due to matrix degradation. The specimens with 3, 6 and 9 mm thickness exhibited maximum water absorption corresponding to 2.6%, 0.7% and 0.5% weight gain, respectively. In general, the results indicated that water uptake and impact properties were affected by thickness and less by water type. Impact properties of prolonged immersed specimens reduced remarkably, and intense failure modes detected almost in all cases. The least sensitive to impact damage were wet specimens with 9 mm thickness as they indicated similar maximum load and absorbed energy for different impact energies.

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Structural Factors Inducing Cracking of Brass Fittings

Materials ◽

10.3390/ma14123255 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3255

Author(s):

Lenka Kunčická ◽

Michal Jambor ◽

Adam Weiser ◽

Jiří Dvořák

Keyword(s):

Chemical Composition ◽

Plastic Flow ◽

Beta Phase ◽

Alpha Phase ◽

Structural Factors ◽

Transmission Electron ◽

Medical Gas ◽

Hot Die Forging ◽

Multiple Step

Cu–Zn–Pb brasses are popular materials, from which numerous industrially and commercially used components are fabricated. These alloys are typically subjected to multiple-step processing—involving casting, extrusion, hot forming, and machining—which can introduce various defects to the final product. The present study focuses on the detailed characterization of the structure of a brass fitting—i.e., a pre-shaped medical gas valve, produced by hot die forging—and attempts to assess the factors beyond local cracking occurring during processing. The analyses involved characterization of plastic flow via optical microscopy, and investigations of the phenomena in the vicinity of the crack, for which we used scanning and transmission electron microscopy. Numerical simulation was implemented not only to characterize the plastic flow more in detail, but primarily to investigate the probability of the occurrence of cracking based on the presence of stress. Last, but not least, microhardness in specific locations of the fitting were examined. The results reveal that the cracking occurring in the location with the highest probability of the occurrence of defects was most likely induced by differences in the chemical composition; the location the crack in which developed exhibited local changes not only in chemical composition—which manifested as the presence of brittle precipitates—but also in beta phase depletion. Moreover, as a result of the presence of oxidic precipitates and the hard and brittle alpha phase, the vicinity of the crack exhibited an increase in microhardness, which contributed to local brittleness.

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Evaluation of Energy Absorption Capabilities of Polyethylene Foam under Impact Deformation

Materials ◽

10.3390/ma14133613 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3613

Author(s):

Baohui Yang ◽

Yangjie Zuo ◽

Zhengping Chang

Keyword(s):

Energy Absorption ◽

Failure Modes ◽

High Strain ◽

Early Stage ◽

High Energy ◽

Test Method ◽

Test Theory ◽

Strain Rates ◽

Impact Properties ◽

The Impact

Foams are widely used in protective applications requiring high energy absorption under impact, and evaluating impact properties of foams is vital. Therefore, a novel test method based on a shock tube was developed to investigate the impact properties of closed-cell polyethylene (PE) foams at strain rates over 6000 s−1, and the test theory is presented. Based on the test method, the failure progress and final failure modes of PE foams are discussed. Moreover, energy absorption capabilities of PE foams were assessed under both quasi-static and high strain rate loading conditions. The results showed that the foam exhibited a nonuniform deformation along the specimen length under high strain rates. The energy absorption rate of PE foam increased with the increasing of strain rates. The specimen energy absorption varied linearly in the early stage and then increased rapidly, corresponding to a uniform compression process. However, in the shock wave deformation process, the energy absorption capacity of the foam maintained a good stability and exhibited the best energy absorption state when the speed was higher than 26 m/s. This stable energy absorption state disappeared until the speed was lower than 1.3 m/s. The loading speed exhibited an obvious influence on energy density.

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Monoclinic and Orthorhombic NaMnO2 for Secondary Batteries: A Comparative Study

Energies ◽

10.3390/en14051230 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1230

Author(s):

Jessica Manzi ◽

Annalisa Paolone ◽

Oriele Palumbo ◽

Domenico Corona ◽

Arianna Massaro ◽

...

Keyword(s):

Structural Parameters ◽

Reversible Capacity ◽

Beta Phase ◽

X Ray Diffraction ◽

Positive Electrodes ◽

Detailed Structural Analysis ◽

Physico Chemical ◽

Sodium Batteries ◽

The Impact ◽

First Time

In this manuscript, we report a detailed physico-chemical comparison between the α- and β-polymorphs of the NaMnO2 compound, a promising material for application in positive electrodes for secondary aprotic sodium batteries. In particular, the structure and vibrational properties, as well as electrochemical performance in sodium batteries, are compared to highlight differences and similarities. We exploit both laboratory techniques (Raman spectroscopy, electrochemical methods) and synchrotron radiation experiments (Fast-Fourier Transform Infrared spectroscopy, and X-ray diffraction). Notably the vibrational spectra of these phases are here reported for the first time in the literature as well as the detailed structural analysis from diffraction data. DFT+U calculations predict both phases to have similar electronic features, with structural parameters consistent with the experimental counterparts. The experimental evidence of antisite defects in the beta-phase between sodium and manganese ions is noticeable. Both polymorphs have been also tested in aprotic batteries by comparing the impact of different liquid electrolytes on the ability to de-intercalated/intercalate sodium ions. Overall, the monoclinic α-NaMnO2 shows larger reversible capacity exceeding 175 mAhg−1 at 10 mAg−1.

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Study on the Operation Model of Colleges Network Learning Propaganda and Public Opinion Guidance Based on the Internet

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.380-384.2104 ◽

2013 ◽

Vol 380-384 ◽

pp. 2104-2108

Author(s):

Chen Liang Li ◽

Ming Xia Zhu

Keyword(s):

Public Opinion ◽

Information Science ◽

Internet Technology ◽

The Internet ◽

C Language ◽

Network Learning ◽

Maximum Value ◽

Network Transmission ◽

The Impact ◽

Important Significance

With the development of computer information science and technology, Internet has a large number of network propaganda and public opinion page every day. Through the network micro message and the micro-blog forwarding, network propaganda and public opinion have the impact on the development and stability of colleges, so the study network propaganda and public opinion has important significance for the development of colleges. Under this background, based on the computer Internet technology, the Internet erection of network propaganda guidance mode are analyzed, and compared with the fuzzy minimum production tree theory and the C language software, the network construction is verified. Finally the iterative process of finding the network transmission is relatively stable, after 800 iterative steps, numerical is slowly increasing, in which the maximum value is about 0.0001. The seven school propaganda is been as the minimum spanning of tree main network, its sum of weighted has been up to 1606.

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