Melt spinning of isotactic polypropylene: Structure development and relationship to mechanical properties

1977 ◽  
Vol 21 (11) ◽  
pp. 3003-3022 ◽  
Author(s):  
Hari P. Nadella ◽  
Helen M. Henson ◽  
Joseph E. Spruiell ◽  
James L. White
1977 ◽  
Vol 21 (9) ◽  
pp. 2341-2358 ◽  
Author(s):  
Vilas G. Bankar ◽  
Joseph E. Spruiell ◽  
James L. White

2015 ◽  
Vol 10 (2) ◽  
pp. 2663-2681
Author(s):  
Rizk El- Sayed ◽  
Mustafa Kamal ◽  
Abu-Bakr El-Bediwi ◽  
Qutaiba Rasheed Solaiman

The structure of a series of AlSb alloys prepared by melt spinning have been studied in the as melt–spun ribbons  as a function of antimony content .The stability  of these structures has  been  related to that of the transport and mechanical properties of the alloy ribbons. Microstructural analysis was performed and it was found that only Al and AlSb phases formed for different composition.  The electrical, thermal and the stability of the mechanical properties are related indirectly through the influence of the antimony content. The results are interpreted in terms of the phase change occurring to alloy system. Electrical resistivity, thermal conductivity, elastic moduli and the values of microhardness are found to be more sensitive than the internal friction to the phase changes. 


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1134
Author(s):  
Bo Seok Song ◽  
Jun Young Lee ◽  
Sun Hwa Jang ◽  
Wan-Gyu Hahm

High-speed melt spinning of thermotropic liquid crystalline polymer (TLCP) resin composed of 4-hydroxybenzoic acid (HBA) and 2-hydroxy-6-napthoic acid (HNA) monomers in a molar ratio of 73/27 was conducted to investigate the characteristic structure development of the fibers under industrial spinning conditions, and the obtained as-spun TLCP fibers were analyzed in detail. The tensile strength and modulus of the fibers increased with shear rate in nozzle hole, draft in spin-line and spinning temperature and exhibited the high values of approximately 1.1 and 63 GPa, respectively, comparable to those of industrial as-spun TLCP fibers, at a shear rate of 70,000 s−1 and a draft of 25. X-ray diffraction demonstrated that the mechanical properties of the fibers increased with the crystalline orientation factor (fc) and the fractions of highly oriented crystalline and non-crystalline anisotropic phases. The results of structure analysis indicated that a characteristic skin–core structure developed at high drafts (i.e., spinning velocity) and low spinning temperatures, which contributed to weakening the mechanical properties of the TLCP fibers. It is supposed that this heterogeneous structure in the cross-section of the fibers was induced by differences in the cooling rates of the skin and core of the fiber in the spin-line.


2009 ◽  
Vol 42 (12) ◽  
pp. 4343-4348 ◽  
Author(s):  
Yan-Hui Chen ◽  
Gan-Ji Zhong ◽  
Yan Wang ◽  
Zhong-Ming Li ◽  
Liangbin Li

2021 ◽  
Vol 23 (2) ◽  
pp. 116-146
Author(s):  
Zinaida Bataeva ◽  
◽  
Alexey Ruktuev ◽  
Ivan Ivanov ◽  
Aleksandr Yurgin ◽  
...  

This paper provides a review of studies on the development and characterization of high-entropy alloys (HEAs). It is structured in the following way. Alloys’ design strategy based on entropy approach. Expectations and modern perceptions. This section describes the initial principles of multicomponent alloys design which provide stable structure and mechanical properties. It is noted that the role of high mixing entropy in the formation of disordered solid solutions and the suppression of the brittle intermetallic phases formation have been significantly reconsidered over time. Currently, obtaining a single-phase solid solution structure is not the main requirement for HEAs. The composition of HEAs. This section describes some typical multicomponent alloys having different elemental compositions. It is shown, that at present time the most studied alloys are based on 3-d transition elements. Using alloys of this group the possibility of providing both high and low values of strength and ductility is shown. Fabrication methods of HEAs. This section describes the methods for the fabrication of high-entropy alloys. It is noted that the most commonly used methods are based on the melting of the initial materials and its subsequent crystallization. Such methods of HEAs fabrication as powder metallurgy, magnetron sputtering, self-propagating high-temperature synthesis, melt spinning, and diffusion welding are also discussed. Structure of HEAs. This section provides the data on HEAs possessing multiphase structure and containing fine nanosized precipitates. Besides, the studies in which HEAs have been obtained in the form of metallic glasses, carbides, oxides, and borides are reviewed. The factors that can affect the structural state of the multicomponent alloys are discussed. The ambiguity of opinions of different research groups is noted. Properties of HEAs. This section mainly concentrates on the mechanical properties of HEAs. However, some other promising properties of HEAs like high wear resistance and reduced diffusivity are also discussed. Plastic deformation of HEAs. This section describes the evolution of the structure and properties of HEAs caused by thermal and mechanical processing. Characterization methods of HEAs. This section lists the characterization techniques, which are most frequently used to study HEAs. The structure of these alloys is mainly studied by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and optical microscopy. The methods for properties measurements are also briefly reviewed. Application of HEAs. This section describes the promising fields of HEAs application. It can be utilized in the aerospace, aircraft, and nuclear industries as well as for car manufacturing, austoelectronics, and in the design of microwave devices. Russian-language publications on HEAs. This section lists the studies, published in the Russian language as well as the thesis, done in Russian universities.


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