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

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.

Study on Shortcut and Simultaneous Nitrification and Denitrification under Low Temperatures

2012 ◽  
Vol 610-613 ◽  
pp. 2047-2052
Author(s):  
Jin Xiang Fu ◽  
Xin Chun Zhang ◽  
Peng Fei Yu
Keyword(s):  
Low Temperature ◽  
Adverse Effects ◽  
Treatment Effect ◽  
Low Temperatures ◽  
Accumulation Rate ◽  
Heating Process ◽  
Nitrite Accumulation ◽  
Simultaneous Nitrification And Denitrification ◽  
Nitrification And Denitrification ◽  
The Impact

This paper studies the impact of cooling and warming on shortcut and simultaneous nitrification and denitrification under low temperature. The results show that the effluent concentration of NH4+-N and TN gradually increased, the nitrite accumulation rate decreased when DO was 0.3~0.5 mg•L-1, sludge return ratio was 300%, PH was 7.5~8.5, temperature dropped from 15 °Cto 8°C. From 10°C to 8°C in cooling, the average nitrite accumulation rate was 58.17% in A (HRT=24h) reactor. During the system heating process, treatment effect of the system gradually changed for the better. From 12°C to 15°Cin heating process, the average nitrite accumulation rate was 74.39% in B (HRT=48h) reactor. The system treatment effect in B reactor was better by contrasting A and B reactors, therefore, we can increase HRT to reduce the adverse effects on the system due to the temperature decreases to enhance TN removal effect of system.

Improvement in Toughness of Transportation and Storage Cask Steel for Spent Nuclear Fuel

2007 ◽  
Author(s):  
Hee Kyung Kwon ◽  
Byoung Koo Kim ◽  
Kuk Cheol Kim ◽  
Keun Ho Song ◽  
Jeong Tae Kim
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Radioactive Material ◽  
Low Alloy Steels ◽  
Tempering Temperature ◽  
Impact Properties ◽  
Temperature Impact ◽  
The Impact

Nuclear power plants have been operated for fifty years. Currently the managements of spent fuel are on progress vigorously. Casks for transportation and/or storage of spent nuclear fuel are usually made of SA350 low alloy steels. The wall thickness of the casks are greater than 300mm. But because leakage of nuclear fuel or radioactive material from unexpected brittle fracture is not acceptable, Nil-ductility transition temperatures of colder than −150°F are needed. The effects of chemical composition and heat treatment on low temperature impact properties of SA350 are investigated in this study. The microstructure of SA350 steel is composed of ferrite and pearlite. The variations of microstructure, low temperature impact properties and strength at room temperature with carbon, vanadium and manganese content are analyzed. To improve the low temperature impact properties, heat treatment at an temperature between quenching and tempering temperature is introduced. With the optimum combination of alloying elements and heat treatment, the impact properties can be improved down to the level of nil-ductility transition temperature −150°F.

scholarly journals The influence of high and low temperatures on the impact properties of glass-epoxy composites

2007 ◽  
Vol 72 (7) ◽  
pp. 713-722 ◽  
Author(s):  
Slavisa Putic ◽  
Marina Stamenovic ◽  
Branislav Bajceta ◽  
Predrag Stajcic ◽  
Srdjan Bosnjak
Keyword(s):  
Low Temperatures ◽  
Composite Structures ◽  
Room Temperature ◽  
Epoxy Composite ◽  
Epoxy Composites ◽  
Temperature Influence ◽  
Impact Properties ◽  
Different Temperatures ◽  
High And Low Temperatures ◽  
The Impact

The aim of this paper is to present the influence of high and low temperatures on the impact properties glass-epoxy composites. The impact strength an is presented for four different glass-epoxy composite structures at three different temperatures, i.e., at room temperature t=20?C, at an elevated temperature t=+50?C and at a low temperature t=-50?C. Standard mechanical testing was carried out on the composite materials with specific masses of reinforcement of 210 g m-2 and 550 g m-2 and orientations 0?/90? and ?45?. Micromechanical analysis of the failure was performed in order to determine real models and mechanisms of crack and temperature influence on the impact properties. .

scholarly journals Charpy Impact Properties of Hydrogen-Exposed 316L Stainless Steel at Ambient and Cryogenic Temperatures

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 625 ◽  
Author(s):  
Le Thanh Hung Nguyen ◽  
Jae-Sik Hwang ◽  
Myung-Sung Kim ◽  
Jeong-Hyeon Kim ◽  
Seul-Kee Kim ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Low Temperatures ◽  
316L Stainless Steel ◽  
Charpy Impact ◽  
Cryogenic Temperatures ◽  
Absorbed Energy ◽  
Impact Properties ◽  
Charging Time ◽  
The Impact

316L stainless steel is a promising material candidate for a hydrogen containment system. However, when in contact with hydrogen, the material could be degraded by hydrogen embrittlement (HE). Moreover, the mechanism and the effect of HE on 316L stainless steel have not been clearly studied. This study investigated the effect of hydrogen exposure on the impact toughness of 316L stainless steel to understand the relation between hydrogen charging time and fracture toughness at ambient and cryogenic temperatures. In this study, 316L stainless steel specimens were exposed to hydrogen in different durations. Charpy V-notch (CVN) impact tests were conducted at ambient and low temperatures to study the effect of HE on the impact properties and fracture toughness of 316L stainless steel under the tested temperatures. Hydrogen analysis and scanning electron microscopy (SEM) were conducted to find the effect of charging time on the hydrogen concentration and surface morphology, respectively. The result indicated that exposure to hydrogen decreased the absorbed energy and ductility of 316L stainless steel at all tested temperatures but not much difference was found among the pre-charging times. Another academic insight is that low temperatures diminished the absorbed energy by lowering the ductility of 316L stainless steel.

scholarly journals Impacts of Low Temperatures on Wolbachia (Rickettsiales: Rickettsiaceae)-Infected Aedes aegypti (Diptera: Culicidae)

2020 ◽  
Vol 57 (5) ◽  
pp. 1567-1574 ◽  
Author(s):  
Meng-Jia Lau ◽  
Perran A Ross ◽  
Nancy M Endersby-Harshman ◽  
Ary A Hoffmann
Keyword(s):  
Life History ◽  
Low Temperature ◽  
Aedes Aegypti ◽  
Disease Transmission ◽  
Low Temperatures ◽  
Temperature Effects ◽  
Life Stage ◽  
Temperature Cycles ◽  
The Impact ◽  
Wolbachia Density

Abstract In recent decades, the occurrence and distribution of arboviral diseases transmitted by Aedes aegypti mosquitoes has increased. In a new control strategy, populations of mosquitoes infected with Wolbachia are being released to replace existing populations and suppress arboviral disease transmission. The success of this strategy can be affected by high temperature exposure, but the impact of low temperatures on Wolbachia-infected Ae. aegypti is unclear, even though low temperatures restrict the abundance and distribution of this species. In this study, we considered low temperature cycles relevant to the spring season that are close to the distribution limits of Ae. aegypti, and tested the effects of these temperature cycles on Ae. aegypti, Wolbachia strains wMel and wAlbB, and Wolbachia phage WO. Low temperatures influenced Ae. aegypti life-history traits, including pupation, adult eclosion, and fertility. The Wolbachia-infected mosquitoes, especially wAlbB, performed better than uninfected mosquitoes. Temperature shift experiments revealed that low temperature effects on life history and Wolbachia density depended on the life stage of exposure. Wolbachia density was suppressed at low temperatures but densities recovered with adult age. In wMel Wolbachia there were no low temperature effects specific to Wolbachia phage WO. The findings suggest that Wolbachia-infected Ae. aegypti are not adversely affected by low temperatures, indicating that the Wolbachia replacement strategy is suitable for areas experiencing cool temperatures seasonally.

scholarly journals Study on Foaming Quality and Impact Property of Foamed Polypropylene Composites

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1375 ◽  
Author(s):  
Wei Gong ◽  
Hai Fu ◽  
Chun Zhang ◽  
Daming Ban ◽  
Xiaogang Yin ◽  
...  
Keyword(s):  
Low Temperature ◽  
Impact Property ◽  
Impact Properties ◽  
Polypropylene Composites ◽  
Polyolefin Elastomer ◽  
Pp Composites ◽  
The Impact ◽  
Foaming Technology ◽  
Thermoplastic Rubber

In the present work, foamed polypropylene (PP) composites were prepared by chemical foaming technology, and the foaming quality and impact property of the foamed PP composites were studied. The results showed that the foaming quality was significantly improved after the introduction of thermoplastic rubber (TPR) and polyolefin elastomer (POE). Meanwhile, it was found that the impact property depended on the intrinsic toughness and contribution of foams (cells) to the PP composites. Furthermore, the data regarding impact property in low temperature showed that when the temperature was between −80 and −20 °C, the impact properties of the foamed PP composites were higher than that of the unfoamed sample, which was due to the impact property being completely contributed by cells under this condition. Meanwhile, when the temperature ranged from −20 to 20 °C, the impact property of the unfoamed sample was higher, which was due to the PP matrix contributing more to the impact property under this temperature. This work significantly improved the foaming quality of foamed PP composites and provided reliable evidence for the improvement of impact property.

The impact of low temperatures in controlling the geographical distribution of plants

1990 ◽  
Vol 326 (1237) ◽  
pp. 585-593 ◽  
Keyword(s):  
Seed Germination ◽  
Low Temperature ◽  
Low Temperatures ◽  
Marked Change ◽  
Tilia Cordata ◽  
Natural Range ◽  
Distribution Limits ◽  
The Impact ◽  
Temperature Responses

The distribution limits of three species, in the British Isles are discussed. For Verbena officinalis and Tilia cordata low temperatures are shown to influence distribution, by limiting the capacity either to flower or to fertilize ovules, respectively. In the case of Umbilicus rupestris , a long-term transplant population beyond the natural geographical limit of the species has evolved new low-temperature responses of seed germination and winter survival. The effect is a marked change of phenology, compared with populations of the species within its natural range, which enhances the capacity of the population to survive in a colder environment.

Effect of Heat Treatment on Impact Properties of TC10 Titanium Alloy

2018 ◽  
Vol 941 ◽  
pp. 725-729
Author(s):  
Gui Hong Qin ◽  
Biao Yan ◽  
Bo Ji ◽  
Wei Lu
Keyword(s):  
Titanium Alloy ◽  
Fracture Morphology ◽  
Beta Phase ◽  
Alpha Phase ◽  
Solution Temperature ◽  
Primary Alpha ◽  
Impact Properties ◽  
Maximum Value ◽  
Fracture Appearance ◽  
The Impact

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.

scholarly journals Optimisation of Direct Battery Thermal Management for EVs Operating in Low-Temperature Climates

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5980 ◽  
Author(s):  
James Jeffs ◽  
Truong Quang Dinh ◽  
Widanalage Dhammika Widanage ◽  
Andrew McGordon ◽  
Alessandro Picarelli
Keyword(s):  
Low Temperature ◽  
Ambient Temperature ◽  
Thermal Management ◽  
Electric Vehicles ◽  
Low Temperatures ◽  
Air Conditioning ◽  
Lithium Ion ◽  
Battery Thermal Management ◽  
Temperature Performance ◽  
The Impact

Electric vehicles (EVs) experience a range reduction at low temperatures caused by the impact of cabin heating and a reduction in lithium ion performance. Heat pump equipped vehicles have been shown to reduce heating ventilation and air conditioning (HVAC) consumption and improve low ambient temperature range. Heating the electric battery, to improve its low temperature performance, leads to a reduction in heat availability for the cabin. In this paper, dynamic programming is used to find the optimal battery heating trajectory which can optimise the vehicle’s control for either cabin comfort or battery performance and, therefore, range. Using the strategy proposed in this research, a 6.2% increase in range compared to no battery heating and 5.5% increase in thermal comfort compared to full battery heating was achieved at an ambient temperature at −7 °C.

scholarly journals Study on impact properties of Ti6211 titanium alloy at different temperatures

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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