scholarly journals Ultrasonic Vibration as a Primary Mixing Tool in Accelerating Aluminum–Copper Alloys Preparation from Their Pure Elements

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 781
Author(s):  
Abdulsalam Muhrat ◽  
Hélder Puga ◽  
Joaquim Barbosa
Keyword(s):  
Ultrasonic Vibration ◽  
Copper Alloys ◽  
Grain Refining ◽  
Alloying Element ◽  
Experimental Conditions ◽  
Melt Temperature ◽  
Cu Alloys ◽  
Aluminum Copper Alloys ◽  
Main Factor

In this study, ultrasonic vibration (USV) was evaluated in preparation of Al–8wt.%Cu alloys at a lab-scale. Moreover, the role of Ti–6Al–4V sonotrode erosion and its contribution in grain refining were analyzed. Based on the experimental conditions/parameters, it was found that the amount of impurities and the associated porosity were significantly reduced in USV treated alloys. Furthermore, USV reduced the time needed for dissolving the alloying element Cu, nevertheless, the best dissolving of Cu in this study was not possible without introducing further holding time. As a result of using a titanium-based sonotrode, a noticeable content of Ti was found in the ultrasonically treated alloys due to sonotrode erosion under USV. The dispersion of TiAl3 promoted, as a main factor, a grain refining effect at relatively constant and high melt temperature, other possible mechanisms of grain refining have been discussed.

Role of Ti and Y in the nucleation of the primary α-Al of Al7075–Ti–Y natural composites and influence of ultrasonic vibration

2021 ◽  
Vol 112 (8) ◽  
pp. 652-664
Author(s):  
Xiao-Hui Chen ◽  
Lei Liu ◽  
Jinbo Li ◽  
Fayun Zhang
Keyword(s):  
Reaction Kinetics ◽  
Grain Refinement ◽  
Ultrasonic Vibration ◽  
Nano Particles ◽  
Influencing Mechanism ◽  
Ultrasonic Time ◽  
Natural Composites ◽  
Corrosion Pits ◽  
Main Factor

Abstract Al7075–Ti–Y natural composites were prepared by using a combination of ultrasonic vibration and casting. The effects of titanium (Ti) and yttrium (Y) on the nucleation of primary α-Al were studied and the influencing mechanism of Y on the TiAl3 formation was analysed. Furthermore, a reaction kinetics model of TiAl3 under ultrasonic vibration was established. The results showed that the uniformly distributed TiAl3 and Al3Y nano-particles resulted in grain refinement. Y changed the morphology of TiAl3 and the appearance of corrosion pits was related to the fact that Y was dissolved within the TiAl3 structure to form Ti(Al,Y)3. The established model revealed that ultrasonic vibration significantly promoted the formation of TiAl3, and that ultrasonic time was the main factor affecting its growth.

scholarly journals On the Role of Dilute Solute Additions on Growth Restriction in Binary Copper Alloys

2020 ◽  
Vol 9 (6) ◽  
pp. 825-832
Author(s):  
M. J. Balart ◽  
F. Gao ◽  
J. B. Patel ◽  
F. Miani
Keyword(s):  
Copper Alloys ◽  
Growth Restriction ◽  
Restriction Factor ◽  
Modeling Framework ◽  
Solute Content ◽  
Grain Length ◽  
Cu Alloys ◽  
Acta Mater ◽  
Columnar Grain

AbstractThe effect of dilute solute additions on growth restriction in binary Cu alloys has been assessed at different degrees of superheat. Columnar grain length values from Northcott’s work (Northcott in J Inst Metals 62:101-136, 1938) for binary Cu alloys were plotted against the corresponding undercooling parameter (P), the reciprocal of the conventional (Qconv.) and true (Qtrue) growth restriction factor (Schmid-Fetzer and Kozlov in Acta Mater 59(15):6133-6144, 2011) values. It was found that there was no correlation between the columnar grain length values and P, 1/Qconv. and 1/Qtrue values for different solutes and cast at the same degree of superheat. Unlike P, Qconv., and Qtrue values, the heuristic growth restriction parameter (β) (Fan et al. in Acta Mater 152, 248-257, 2018) modeling framework in conjunction with the critical solute content (C*) for growth restriction fitted well to binary Cu alloys.

Effects of Mold Temperature and Casting Temperature on Hot Cracking in Al-4.5 wt.% Cu Alloy

2013 ◽  
Vol 747 ◽  
pp. 623-626
Author(s):  
R. Burapa ◽  
S. Rawangwong ◽  
J. Chatthong ◽  
Worapong Boonchouytan
Keyword(s):  
High Resistance ◽  
Copper Alloys ◽  
Mold Temperature ◽  
Hot Cracking ◽  
The Other ◽  
Casting Temperature ◽  
Experimental Conditions ◽  
Cu Alloy ◽  
Aluminum Copper Alloys ◽  
Cracking Tendency

Hot cracking is an important defect that occurs during solidification of aluminum-copper alloys. In this present work, the effects of mold temperature and casting temperature on hot cracking in the Al-4.5 wt.% Cu alloy has been studied using a ring mold for hot cracking assessment. For the experimental conditions, three mold temperatures between 150 and 350°C and three casting temperatures between 670 and 770°C were studied and Al-7 wt.% Si alloy was used as reference for comparison. The results showed Al-7 wt.% Si alloy has high resistance to hot cracking and no hot cracking forms under three different mold temperatures, while Al-4.5 wt.% Cu alloy shows significant hot cracking tendency under the same casting conditions. The severity of hot cracking in Al-4.5 wt.% Cu alloy decreased significantly with increasing the mold temperature and decreasing the casting temperature. On the other hand, an increasing casting temperature resulted in severer hot cracking in Al-4.5 wt.% Cu alloy.

scholarly journals The Influence of Nickel and Tin Additives on the Microstructural and Mechanical Properties of Al-Zn-Mg-Cu Alloys

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Haider T. Naeem ◽  
Kahtan S. Mohammed ◽  
Khairel R. Ahmad ◽  
Azmi Rahmat
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloys ◽  
Base Alloy ◽  
Copper Alloys ◽  
Aging Treatment ◽  
Alloying Element ◽  
Cu Alloys ◽  
Different Temperatures ◽  
Retrogression And Reaging ◽  
Better Than

The effects of nickel and nickel combined tin additions on mechanical properties and microstructural evolutions of aluminum-zinc-magnesium-copper alloys were investigated. Aluminum alloys containing Ni and Sn additives were homogenized at different temperatures conditions and then aged at 120°C for 24 h (T6) and retrogressed at 180°C for 30 min and then reaged at 120°C for 24 h (RRA). Comparison of the ultimate tensile strength (UTS) of as-quenched Al-Zn-Mg-Cu-Ni and Al-Zn-Mg-Cu-Ni-Sn alloys with that of similar alloys which underwent aging treatment at T6 temper showed that gains in tensile strengths by 385 MPa and 370 MPa were attained, respectively. These improvements are attributed to the precipitation hardening effects of the alloying element within the base alloy and the formation of nickel/tin-rich dispersoid compounds. These intermetallic compounds retard the grain growth, lead to grain refinement, and result in further strengthening effects. The outcomes of the retrogression and reaging processes which were carried on aluminum alloys indicate that the mechanical strength and Vickers hardness have been enhanced much better than under the aging at T6 temper.

Stability of Chemical Order in Ni4Mo Alloy under Fast Electron Irradiation

1977 ◽  
Vol 35 ◽  
pp. 48-49
Author(s):  
R. W. Carpenter ◽  
E. A. Kenik
Keyword(s):  
Copper Alloys ◽  
Range Order ◽  
Local Composition ◽  
Chemical Order ◽  
Cu Alloys ◽  
Ti Alloys ◽  
Void Swelling ◽  
Aluminum Copper Alloys ◽  
Modulated Structures ◽  
The Stability

Short-range order (SRO) or clustering strongly influences swelling in alloys. For example, Al-Cu alloys containing G-P zones, Cu-Ti alloys containing modulated structures, and Ni-Mo alloys containing various degrees of chemical order are all resistant to void swelling caused by displacive irradiation at elevated temperature. Conversely, displacive particle irradiations may change the configuration of local composition variations. When aluminum-copper alloys containing G-P zones are irradiated with 1 MeV electrons a transformation to 'θ' occurs, and the usually observed θ” state is not observed. This paper presents the results of an experimental investigation of order stability in Ni—20 at. % Mo alloys during irradiation with 1 MeV electrons. This alloy is especially useful for studying the stability of order during irradiation because the symmetry of the intensity distribution in reciprocal space corresponding to SRO is quite different from that corresponding to the Dla long-range order (LRO) observed at thermal equilibrium in this alloy.

Characteristics of Pressure Buildup From Local Fuel-Coolant Interactions in a Simulated Molten Fuel Pool

2014 ◽  
Author(s):  
Songbai Cheng ◽  
Ken-ichi Matsuba ◽  
Mikio Isozaki ◽  
Kenji Kamiyama ◽  
Tohru Suzuki ◽  
...  
Keyword(s):  
Severe Accident ◽  
Water Volume ◽  
Reactor Safety ◽  
Experimental Conditions ◽  
Melt Temperature ◽  
Pressure Buildup ◽  
Severe Accidents ◽  
Series Of Experiments ◽  
Boiling Mode

Studies on local fuel-coolant interactions (FCI) in a molten pool are important for severe accident analyses of sodium-cooled fast reactors (SFRs). To clarify the mechanisms underlying this interaction, in this study a series of experiments was conducted by delivering a given quantity of water into a simulated molten fuel pool (formed with a low-melting-point alloy). Based on the experimental data obtained from a variety of conditions, including difference in water volume, melt temperature and water subcooling, the characteristics of pressure-buildup during local FCIs was investigated. It is found that under our experimental conditions the water volume and melt temperature have remarkable impact on the interaction, while the role of water subcooling seems to be less prominent. The performed analyses also suggest that the pressurization from local FCIs should be intrinsically limited, due to a suppressing role caused by the increasing of coolant volume entrapped within the pool as well as the transition of boiling mode. Current work, which gives a palette of favorable data for a better understanding and an improved estimation of severe accidents in SFRs, is expected to benefit future analyses and verifications of computer models developed in advanced fast reactor safety analysis codes.

Role of Ti and Y in the nucleation of the primary α-Al of Al7075–Ti–Y natural composites and influence of ultrasonic vibration

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiao-Hui Chen ◽  
Lei Liu ◽  
Jinbo Li ◽  
Fayun Zhang
Keyword(s):  
Reaction Kinetics ◽  
Grain Refinement ◽  
Ultrasonic Vibration ◽  
Nano Particles ◽  
Influencing Mechanism ◽  
Ultrasonic Time ◽  
Natural Composites ◽  
Corrosion Pits ◽  
Main Factor

Abstract Al7075–Ti–Y natural composites were prepared by using a combination of ultrasonic vibration and casting. The effects of titanium (Ti) and yttrium (Y) on the nucleation of primary α-Al were studied and the influencing mechanism of Y on the TiAl3 formation was analysed. Furthermore, a reaction kinetics model of TiAl3 under ultrasonic vibration was established. The results showed that the uniformly distributed TiAl3 and Al3Y nano-particles resulted in grain refinement. Y changed the morphology of TiAl3 and the appearance of corrosion pits was related to the fact that Y was dissolved within the TiAl3 structure to form Ti(Al,Y)3. The established model revealed that ultrasonic vibration significantly promoted the formation of TiAl3, and that ultrasonic time was the main factor affecting its growth.

Surfaces Modification of Al-Cu Alloys by Plasma-Assisted CVD

2013 ◽  
Vol 199 ◽  
pp. 496-501 ◽  
Author(s):  
Karol Kyzioł ◽  
Łukasz Kaczmarek ◽  
Stanisława Jonas
Keyword(s):  
Wear Resistance ◽  
Copper Alloys ◽  
Chemical Vapour ◽  
Argon Plasma ◽  
High Strength ◽  
Aviation Industry ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Aluminum Copper Alloys ◽  
Pre Treatment

Aluminum-copper alloys (Al-Cu) are nowadays widely used in various applications, mainly in automotive and aviation industry, because of their unique properties such as high strength, low density and good corrosion resistance. However, usages of aluminum alloys are partially limited due to their reduced hardness, wear resistance and poor tribological parameters. Desired useful parameters can be improved by application of PA CVD technology. This work presents the results concerning determination and analysis of the structure and the selected properties of the modified surfaces of Al-Cu alloys (2xxx series) that were prepared using plasma assisted MW CVD (Micro-Wave Chemical Vapour Deposition) method. To ensure effectiveness of the substrate modification process, the covered surface was subjected to pre-treatment with argon plasma and/or nitriding process. In conclusion, the research has confirmed that the wear resistance of the Al-Cu alloy can be successfully modified by application of MW CVD technique. The obtained results can serve as a basis in the design of the technology of a-Si:C:N:H layers for diverse applications.

Site of Lysosome Production During Hepatic Injury

1969 ◽  
Vol 27 ◽  
pp. 348-349
Author(s):  
Nalin J. Unakar
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Mouse Liver ◽  
Hepatic Injury ◽  
Close Approximation ◽  
Experimental Conditions ◽  
Toxic Injury

The increased number of lysosomes as well as the close approximation of lysosomes to the Golgi apparatus in tissue under variety of experimental conditions is commonly observed. These observations suggest Golgi involvement in lysosomal production. The role of the Golgi apparatus in the production of lysosomes in mouse liver was studied by electron microscopy of liver following toxic injury by CCI4.

Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster

Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 79-86 ◽  
Author(s):  
P. V. Elizar’ev ◽  
D. V. Lomaev ◽  
D. A. Chetverina ◽  
P. G. Georgiev ◽  
M. M. Erokhin
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Transcription Terminator ◽  
Response Elements ◽  
Polycomb Response Elements ◽  
The Individual ◽  
Multicellular Organisms ◽  
Different Cell Types ◽  
Main Factor

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesnt prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.

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