Smart Alloys for Automotive Bumpers

2015 ◽  
Vol 809-810 ◽  
pp. 578-583
Author(s):  
Radu Cristian Crăciun ◽  
Sergiu Stanciu ◽  
Ramona Cimpoeşu ◽  
Florin Săndulache ◽  
Adela Ioana Ursanu Dragos ◽  
...  

Bumper beam absorbs the accidental kinetic energy by deflection in low-speed impact and by deformation in high-speed impact. Based on the last years necessity of lighter materials and safer usage of vehicles we try to come with a new class of materials for bumper systems. Analyze of metallic materials is cheaper when the analyze take place on a computer avoiding the metallic loss or energy consume. We present few results obtained in Catia software about the behavior of some metallic materials under external solicitations in function of the mechanical properties of metallic elements, geometry of the element, restrains and solicitation points. Shape memory alloy are smart materials that can use the external mechanical energy damping to thermal energy in bumper applications. In martensite to austenite domain we observe an increase of damping mechanical capacity with possible applications in bumper systems.

Author(s):  
O Kocar ◽  
H Livatyalı

An aluminized 22MnB5 (Boron) steel sheet, used for structural parts in the automotive industry, was subjected to press-hardening followed by austenitizing, both in a conventional furnace and via the conductive (electric resistance) heating method, an innovative technique based on the Joule’s principle for fast heating of the sheet metal. Conductive heating presents a number of advantages over the in-furnace heating method. These include a more efficient use of energy, as well as the requirement of less time and space for heating, thus lowering costs. After press-hardening was performed using both methods, the microstructural and mechanical characterizations of both specimens were examined for optical microscopy, hardness, tensile strength, and high-speed impact tests. The results showed that the press-hardening process transformed the ferritic–pearlitic microstructure in the as-received state into martensite after die quenching and caused a substantial increase in hardness and strength at the expense of ductility and impact toughness. On the other hand, no significant difference was observed in either the microstructure or mechanical properties with respect to the heating method used. The results obtained in the present investigation concur with the findings of current literature.


2012 ◽  
Vol 727-728 ◽  
pp. 1785-1788
Author(s):  
Milena Costa da Silva ◽  
Sara Verusca de Oliveira ◽  
Tomás Jefférson Alves de Mélo ◽  
Edcleide Maria Araújo

Nanocomposites are hybrid materials that can be obtained with, three, two or bust one-dimensional in nanoscale found in particles dispersed in the matrix. By presenting a nanometric structure, this new class of materials may have only properties, different from traditional composites and their constituents, which may be established in the synthesis process. The aim of this work is prepare nanocomposites of HDPE/ bentonite clay by melt intercalation technique. Systems were evaluated for the presence of untreated clay and chemically treated (organoclay) with two different types of quaternary ammonium salts, Cetremide and Dodigen. In the preparation of nanocomposites were obtained concentrated using a high speed mixer and then the nominal percentage of clay was dispersed in a twin screw extruder corrotacional. The systems were characterized by X-ray diffraction and mechanical properties. The XRD patterns of nanocomposite of HDPE/organoclay suggest a not intercalated structure. The mechanical properties of nanocomposites presented reducing values in relation to pure polymer.


2017 ◽  
Vol 750 ◽  
pp. 175-179
Author(s):  
Florin Săndulache ◽  
Sergiu Stanciu ◽  
Nicanor Cimpoeşu ◽  
Ramona Cimpoeşu ◽  
Teodor Stanciu

Biodegradable metallic materials gain space in implantable materials field based on the applications that can fulfill. Beside Mg-based alloys a new class of metallic materials is under development, alloys based on Fe, in order to improve the corrosion rate, one of the disadvantages of magnesium alloys, and the mechanical properties of the implant. In this article we present the steps took to obtain a biodegradable FeMnSi alloy with metallic additions and few preliminary results about the chemical composition (X-ray dispersive energy analyze EDS) of the sample and the influence of hardening heat treatment on chemical composition. After the melting and pouring stages the new material was analyzed.


2014 ◽  
Vol 66 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Serkan Büyükdoğan ◽  
Süleyman Gündüz ◽  
Mustafa Türkmen

Purpose – The paper aims to provide new observations about static strain ageing in aluminium (Al) alloys which are widely used in structural applications. Design/methodology/approach – The present work aims to provide theoretical and practical information to industries or researchers who may be interested in the effect of static strain ageing on mechanical properties of Al alloys. The data are sorted into the following sections: introduction, materials and experimental procedure, results and discussion and conclusions. Findings – Tensile strength, proof strength (0.2 per cent) and percentage elongation measurement were used to investigate the effect of strain ageing on the mechanical properties. Wear tests were performed by sliding the pin specimens, which were prepared from as-received, solution heat-treated, deformed and undeformed specimens after ageing, on high-speed tool steel (64 HRC). It is concluded that the variations in ageing time improved the strength and wear resistance of the 6063 Al alloy; however, a plastically deformed solution-treated alloy has higher strength and wear resistance than undeformed specimens for different ageing times at 180°C. Practical implications – A very useful source of information for industries using or planning to produce Al alloys. Originality/value – This paper fulfils an identified resource need and offers practical help to the industries.


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.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Qingzhong Mao ◽  
Yusheng Zhang ◽  
Yazhou Guo ◽  
Yonghao Zhao

AbstractThe rapid development of high-speed rail requires copper contact wire that simultaneously possesses excellent electrical conductivity, thermal stability and mechanical properties. Unfortunately, these are generally mutually exclusive properties. Here, we demonstrate directional optimization of microstructure and overcome the strength-conductivity tradeoff in copper wire. We use rotary swaging to prepare copper wire with a fiber texture and long ultrafine grains aligned along the wire axis. The wire exhibits a high electrical conductivity of 97% of the international annealed copper standard (IACS), a yield strength of over 450 MPa, high impact and wear resistances, and thermal stability of up to 573 K for 1 h. Subsequent annealing enhances the conductivity to 103 % of IACS while maintaining a yield strength above 380 MPa. The long grains provide a channel for free electrons, while the low-angle grain boundaries between ultrafine grains block dislocation slip and crack propagation, and lower the ability for boundary migration.


2021 ◽  
Vol 1121 (1) ◽  
pp. 012009
Author(s):  
S Lee ◽  
R Muchime ◽  
R Matsumoto ◽  
H Utsunomiya

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