scholarly journals A Method for Evaluating the Impact Wear Behavior of Multilayer TiN/Ti Coating

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 132 ◽  
Author(s):  
Xin Cao ◽  
Weisheng Xu ◽  
Weifeng He
Keyword(s):  
Wear Behavior ◽  
Failure Mechanisms ◽  
High Stress ◽  
Impact Wear ◽  
Maximum Value ◽  
Impact Peak ◽  
Energy Dissipated ◽  
The Impact ◽  
Impact Zones ◽  
Circular Cracks

An energy-controlled cycling impact test was applied to evaluate the impact wear behavior of hard coating. A multilayer TiN/Ti coating with a total thickness of ~10 μm, containing two TiN layers and two Ti layers, with the thickness ratio of these two kinds of the layers being 9:1, was chosen as the research object. The impact velocities were 60, 120, and 180 mm/s, and the impact cycles were 10, 102, 103, and 104, respectively. Damage morphology observation and numerical simulation were used to analyze the failure mechanisms. The results show that the contact time keeps almost constant under different impact velocities and cycles. Impact peak forces remain unchanged with increasing cycles at the same velocity, but they increase linearly with impact velocities, reaching a maximum value of 262.26 N at 180 mm/s. The energy dissipated rate (EDR) increases from 31.58% at 60 mm/s to 35.59% at 180 mm/s, indicating the degenerative toughness. Two impact-wear failure mechanisms are found in impact zones of the coating; these are peeling and circular cracks. Peelings are induced by cycling high-stress gradients in hard layers and interfaces. Circular cracks are caused by cycling tensile stresses in the form of fatigue at the edge of impacted pits.

Wear behaviors of WC and TiC on co matrix composites under three-body impact abrasive wear condition

2019 ◽  
Vol 71 (7) ◽  
pp. 893-900 ◽  
Author(s):  
Lei Dong ◽  
Xiaoyu Zhang ◽  
Kun Liu ◽  
Xiaojun Liu ◽  
Ruiming Shi ◽  
...  
Keyword(s):  
Wear Rate ◽  
Abrasive Wear ◽  
Impact Energy ◽  
Wear Behavior ◽  
High Impact ◽  
Impact Wear ◽  
High Impact Energy ◽  
Content Type ◽  
Three Body ◽  
The Impact

Purpose The purpose of this paper is to investigate the tribological properties of the WC/TiC-Co substrate under different loading conditions under three impact abrasive wear conditions. Design/methodology/approach The three body collisional wear behavior of Co alloy with WC and TiC at three impact energy was studied from 1 to 3 J. Meanwhile, the microstructure, hardness, phase transformation and wear behavior of these specimens were investigated by scanning electron microscopy, Rockwell hardness (HRV), EDS and impact wear tester. The resulting wear rate was quantified by electronic balance measurements under different pressures. Findings The specific wear rate increases with the increase of the nonlinearity of the impact energy and the increase in the content of WC or TiC. The effect of TiC on wear rate is greater than that of WC, but the hardness is smaller. The wear characteristics of the samples are mainly characterized by three kinds of behavior, such as cutting wear, abrasive wear and strain fatigue wear. The WC-Co with fewer TiC samples suffered heavier abrasive wear than the more TiC samples under both low and high impact energy and underwent fewer strain fatigue wears under high impact energy. Originality/value The experimental results show that the wear resistance of the Co alloy is improved effectively and the excellent impact wear performance is achieved. The results can be used in cutting tools such as coal mine cutting machines or other fields.

Investigation on the impact wear behavior of 2.25Cr–1Mo steel at elevated temperature

Wear ◽  
2021 ◽  
pp. 203740
Author(s):  
Xu-dong Chen ◽  
Li-wen Wang ◽  
Ling-yun Yang ◽  
Rui Tang ◽  
Yan-qing Yu ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Wear Behavior ◽  
Impact Wear ◽  
The Impact

Real-time cryo-deformation of polypropylene and impact-modified polypropylene in the transmission electron microscope

1993 ◽  
Vol 51 ◽  
pp. 892-893
Author(s):  
Robert C. Cieslinski ◽  
H. Craig Silvis ◽  
Daniel J. Murray
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Failure Mechanisms ◽  
Brittle Transition ◽  
Molded Part ◽  
Transmission Electron ◽  
Solvent Cast ◽  
The Impact ◽  
Annealed Copper ◽  
Dynamic Plane

An understanding of the mechanical behavior polymers in the ductile-brittle transition region will result in materials with improved properties. A technique has been developed that allows the realtime observation of dynamic plane stress failure mechanisms in the transmission electron microscope. With the addition of a cryo-tensile stage, this technique has been extented to -173°C, allowing the observation of deformation during the ductile-brittle transition.The technique makes use of an annealed copper cartridge in which a thin section of bulk polymer specimen is bonded and plastically deformed in tension in the TEM using a screw-driven tensile stage. In contrast to previous deformation studies on solvent-cast films, this technique can examine the frozen-in morphology of a molded part.The deformation behavior of polypropylene and polypropylene impact modified with EPDM (ethylene-propylene diene modified) and PE (polyethylene) rubbers were investigated as function of temperature and the molecular weight of the impact modifier.

scholarly journals Land Subsidence Estimation for Aquifer Drainage Induced by Underground Mining

Energies ◽  
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.

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

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.

Preparation and curing behavior of high-stress solid propellant binder based on polydicyclopentadiene

2016 ◽  
Vol 29 (8) ◽  
pp. 931-936 ◽  
Author(s):  
Qili Sun ◽  
Song Ma ◽  
Zhen Ge ◽  
Yunjun Luo
Keyword(s):  
Ring Opening ◽  
Solid Propellant ◽  
First Generation ◽  
High Stress ◽  
Mechanical Analysis ◽  
Polymerization Reaction ◽  
Curing Behavior ◽  
Maximum Value ◽  
Cure Time ◽  
Propellant Binder

The ring-opening metathesis polymerization reaction of dicyclopentadiene (DCPD) was carried out using Grubbs first generation catalyst. Fourier transform infrared (FTIR), dynamic-thermo mechanical analysis (DMA), and Raman spectroscopy were used to investigate the curing behavior of this polymer. The FTIR results showed that DCPD had not cured completely and the polymers were composed of linear and cross-linked polydicyclopentadiene (PDCPD). The DMA test showed that the polymer possesses the glass transition temperature of linear PDCPD and cross-linked PDCPD, which had also proved the FTIR result. Furthermore, in order to explain the strange phenomenon that the band at 3004 cm−1 should have been detected in infrared spectrum, the Raman spectrum of PDCPD was applied to analyze the bonding mechanism of =C–H bond in the process of polymerization. Moreover, the real-time FTIR result cure formula showed that the cure degree increases first then constants trend with cure time of increasing, the cure degree reached the maximum value (96.76%) at 60°C for 192 h.

Deceleration of sliding motorcycles (mainly scooters) in accident reconstructions

2017 ◽  
Vol 232 (7) ◽  
pp. 866-876 ◽  
Author(s):  
Carlo Cialdai ◽  
Dario Vangi ◽  
Antonio Virga
Keyword(s):  
Urban Areas ◽  
Test Session ◽  
Road Accidents ◽  
Factors Affecting ◽  
Different Types ◽  
Energy Dissipated ◽  
Comparison Of The Results ◽  
Two Wheeler ◽  
The Impact ◽  
Good Agreement

This paper presents an analysis of the situation in which a two-wheeler (i.e. a motorcycle, where the term motorcycles includes scooters) falls over to the side and then successively slides; this typically occurs in road accidents involving this type of vehicle. Knowing the deceleration rate of the sliding phase allows the kinetic energy dissipated and the speed of the motorcycle just before the fall to the ground to be calculated. These parameters are very important in the analysis and reconstruction of accidents. The work presented in this paper was developed in two experimental test sessions on fully faired motorcycles which are mainly of the scooter type and widely used in urban areas. In the first session, sliding tests were carried out, with the speed in the range 10–50 km/h, on three different types of road surface. Analysis of the evidence allowed the dissipative main phases of motion of the motorcycle (the impact with the ground, the rebounds and the stabilized swiping) to be identified and some factors affecting the phenomenon to be studied. The coefficient of average deceleration was calculated using two typical equations. The second test session consisted of drag tests. In these tests, the motorcycle, which had previously laid on its side, was dragged for a few metres at a constant speed of about 20 km/h, while the drag force was measured. A comparison of the results obtained in these tests with those obtained in the sliding tests yielded very good agreement in the coefficients of deceleration.

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