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.

The rate of solidification and the effects of local composition on the subsequent nucleation of Al2Cu2Mn3 dispersoid phase in Al-4Cu-0.3Fe-0.4Mn-0.2Si alloys

2004 ◽  
Vol 120 ◽  
pp. 61-68
Author(s):  
T. L. Zoeller ◽  
T. H. Sanders
Keyword(s):  
Aluminum Alloy ◽  
Phase Particle ◽  
Solidification Rate ◽  
Copper Alloys ◽  
Grain Morphology ◽  
Second Phase ◽  
Thermal Treatments ◽  
Local Composition ◽  
Aluminum Copper Alloys ◽  
Alloy Microstructure

Following solidification, an aluminum alloy microstructure is highly segregated. The microstructure consists of cored dendrites with various soluble and insoluble phases present in the inter-dendritic regions. The solidification rate has a marked effect on the amount of coring as well as grain dimensions and second phase particle size and spacing. Post-solidification cooling rates as well as subsequent heat treatments also affect the evolution of the microstructure. Understanding the effects of these thermal treatments is important in explaining differences in microstructures that are observed in alloys of identical compositions. The focus of this study is to determine the interaction between the coring of copper across dendrites during solidification and the precipitation of dispersoids during the homogenization treatments of an alloy. An aluminum alloy whose composition is in the range of Al-4Cu-0.3Fe-0.4Mn-0.2Si is ideally suited for this study for several reasons. First it is similar to a host of commercial aluminum copper alloys, and the presence of Mn, Fe, and Si affect the distribution of particles that control grain morphology in these alloys. Preliminary experimental results are discussed. Current numerical analysis techniques will be examined and possible methods to treat the problem will be presented.

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.

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.

Development of the Snoek Anelastic Relaxation Correlated with Oxygen in β-Ti Alloys

2019 ◽  
Vol 298 ◽  
pp. 59-63 ◽  
Author(s):  
Zheng Cun Zhou ◽  
J. Du ◽  
S.Y. Gu ◽  
Y.J. Yan
Keyword(s):  
Internal Friction ◽  
Physical And Mechanical Properties ◽  
Peak Height ◽  
Relaxation Peak ◽  
Interstitial Oxygen ◽  
Internal Friction Peak ◽  
Β Phase ◽  
Ti Alloys ◽  
Interstitial Atoms ◽  
The Stability

The β-Ti alloys exhibit excellent shape memory effect and superelastic properties. The interstitial atoms in the alloys have important effect on their physical and mechanical properties. For the interstitial atoms, the internal friction technique can be used to detect their distributions and status in the alloys. The anelastic relaxation in β-Ti alloys is discussed in this paper. β-Ti alloys possesses bcc (body center body) structure. The oxygen (O) atoms in in the alloys is difficult to be removed. The O atoms located at the octahedral sites in the alloys will produce relaxation under cycle stress. In addition, the interaction between the interstitial atoms and substitute atoms, e.g., Nb-O,Ti-O can also produce relaxation. Therefore, the observed relaxational internal friction peak during the measuring of internal friction is widened. The widened multiple relaxation peak can be revolved into Debye,s elemental peaks in Ti-based alloys. The relaxation peak is associated with oxygen movements in lattices under the application of cycle stress and the interactions of oxygen-substitute atoms in metastable β phase (βM) phase for the water-cooled specimens and in the stable β (βS) phase for the as-sintered specimens. The damping peak height is not only associated with the interstitial oxygen, but also the stability and number of βM in the alloys.

scholarly journals Irradiation Hardening Behavior of He-Irradiated V–Cr–Ti Alloys with Low Ti Addition

2020 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Ken-ichi Fukumoto ◽  
Yoshiki Kitamura ◽  
Shuichiro Miura ◽  
Kouji Fujita ◽  
Ryoya Ishigami ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Optimum Composition ◽  
Solid Solution Hardening ◽  
Irradiation Hardening ◽  
Hardening Behavior ◽  
Ti Alloys ◽  
Void Swelling ◽  
Before And After ◽  
Cr Addition ◽  
Ti Addition

A set of V–(4–8)Cr–(0–4)Ti alloys was fabricated to survey an optimum composition to reduce the radioactivity of V–Cr–Ti alloys. These alloys were subjected to nano-indenter tests before and after 2-MeV He-ion irradiation at 500 °C and 700 °C with 0.5 dpa at peak damage to investigate the effect of Cr and Ti addition and gas impurities for irradiation hardening behavior in V–Cr–Ti alloys. Cr and Ti addition to V–Cr–Ti alloys for solid–solution hardening remains small in the unirradiated V–(4–8)Cr–(0–4)Ti alloys. Irradiation hardening occurred for all V–Cr–Ti alloys. The V–4Cr–1Ti alloy shows the highest irradiation hardening among all V–Cr–Ti alloys and the gas impurity was enhanced to increase the irradiation hardening. These results may arise from the formation of Ti(CON) precipitate that was produced by He-ion irradiation. Irradiation hardening of V–Cr–1Ti did not depend significantly on Cr addition. Consequently, for irradiation hardening and void-swelling suppression, the optimum composition of V–Cr–Ti alloys for structural materials of fusion reactor engineering is proposed to be a highly purified V–(6–8)Cr–2Ti alloy.

scholarly journals Numerical investigation of mechanical properties of aluminum-copper alloys at nanoscale

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Satyajit Mojumder ◽  
Md Shajedul Hoque Thakur ◽  
Mahmudul Islam ◽  
Monon Mahboob ◽  
Mohammad Motalab
Keyword(s):  
Mechanical Properties ◽  
Numerical Investigation ◽  
Copper Alloys ◽  
Aluminum Copper Alloys
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