The Relationship of the Inclusions and Hydrogen Content in the Molten Aluminum Alloys

2000 ◽  
Vol 331-337 ◽  
pp. 325-330
Author(s):  
Hongri Cong ◽  
Xiu Fang Bian
Keyword(s):  
Aluminum Alloys ◽  
Hydrogen Content ◽  
Molten Aluminum ◽  
Relationship Of ◽  
The Relationship

Effect of Porosity on Residual Stress of 2024-Aluminum GTAW Specimen

2016 ◽  
Vol 872 ◽  
pp. 28-32 ◽  
Author(s):  
Pattarawadee Poolperm ◽  
Wasawat Nakkiew
Keyword(s):  
Residual Stress ◽  
Aluminum Alloys ◽  
Welding Speed ◽  
Fatigue Crack Initiation ◽  
Welding Process ◽  
The Body ◽  
Tensile Residual Stress ◽  
Welding Parameters ◽  
Relationship Of ◽  
The Relationship

Aluminum alloys are used widely in many applications due to its low in density which can lead to a lightweight product. A high percentage of Cu in the chemical composition of the 2024 aluminum alloys helps withstand the occurrence of corrosion as well. Thus, aluminum alloy grade 2024 is used as a material for several parts in aircraft and spacecraft components, (e.g. the body of commercial airplanes), as well as parts in many other applications. Gas Tungsten Arc Welding (GTAW) is used widely in joining material parts together. Inappropriate welding parameters usually cause problems such as porosity in the welding. The occurrence of porosity is undesirable in welding because it can affect the strength of the welding area as well as other properties. Tensile residual stress near the surface of the material expedites the fatigue crack initiation. The relationship of porosity and residual stress for GTAW parts was very limited in literatures. Therefore, the objective of this research was to investigate the relationship of porosity to the occurrence of residual stress after the welding process. Full factorial design of experimental technique was used for setting up welding conditions of the GTAW. The specimen with highest porosity was selected for further analysis of its effect on residual stress. Porosity was analyzed by the radiographic testing (RT) and the residual stress was measure by X-ray diffraction (XRD) using sin2 method. The results showed that the highest porosity in the welded bead was found at the current of 130 A, the welding speed of 210 mm./min., and the wire feed rate of 700 mm./min. The results also suggested that lower current and welding speed caused an increase in porosity. The residual stress results on both longitude and transverse directions showed tensile residual stress at locations around the welded bead area.

Study on the Relationship of Hydrogen Content and Ultrasonic Propagation Properties

2007 ◽  
Vol 353-358 ◽  
pp. 2549-2552
Author(s):  
Lei Zhang ◽  
Shi Hua Tang ◽  
Hong Liang Pan
Keyword(s):  
Hydrogen Content ◽  
Petrochemical Industry ◽  
Hydrogen Attack ◽  
Hydrogen Corrosion ◽  
Metal Materials ◽  
Material Conditions ◽  
Ultrasonic Propagation ◽  
Propagation Properties ◽  
Relationship Of ◽  
The Relationship

Hydrogen-induced corrosion is a common damage in petrochemical industry. It can rise crack and bubbling on the surface of metal materials when the hydrogen corrosion is in the stage of severity. In the present, it is hard to evaluate the material conditions nondestructively under hydrogen attack. In this paper, the possibility of the relationship between ultrasonic propagation properties and the content of hydrogen corrosion was investigated. We have found that the surface wave velocity is a parameter, which can be directly correlated with the hydrogen content. The sensitivity has been found to be acceptable.

An Investigation on the Hydrogen Content in Al-12Si Alloy Melt

2010 ◽  
Vol 97-101 ◽  
pp. 785-788
Author(s):  
Zheng Bin Xu ◽  
Yong Zhi Zou ◽  
Wen Chao Wang ◽  
Jian Min Zeng
Keyword(s):  
Relative Humidity ◽  
Hydrogen Content ◽  
Sudden Change ◽  
Liquid Structure ◽  
Regression Equations ◽  
Ambient Relative Humidity ◽  
Physical Mass ◽  
Relationship Of ◽  
The Relationship ◽  
Holding Temperature

This present work investigate the hydrogen content in Al-12Si alloy at different holding temperatures of 993K, 1023K, and 1053K and under different ambient relative humidity 30%RH, 50%RH, 80%RH. The relationship of the hydrogen content with atmosphere relative humidity and the reaction time was investigated. A HYSCAN II analyzer was used to evaluate the hydrogen content in aluminum melts. The experimental results show that the hydrogen content increased with the holding temperature and the relative humidity. At the temperature 1053K, the hydrogen content has an inverse change. The hydrogen content is more depend on the liquid structure than physical mass transfer and chemical reaction because of the sudden change in liquid microstructure. A group of kinetic regression equations of the hydrogen absorption in Al-12Si melts was obtained.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

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