scholarly journals Superior Properties of Ultra-fine-grained Steels

10.14311/572 ◽  
2004 ◽  
Vol 44 (3) ◽  
Author(s):  
J. I. Leinonen

A description of the improved mechanical properties obtained in ultra-fine-grained steels up to now will be presented in this paper, and some potential applications of these new generation steels will be described. In addition, the principle and implementation of a novel hot rolling process developed by the author will be introduced. This novel Thermomechanical Nonrecrystallisation Control Process (TNCP) has been shown to give an ultra-fine ferrite (uff) structure with grain sizes of 2 to 3mm in various test steels, thus resulting in super-toughness. Charpy V impact test results suggest that some of these steels could still be tough at temperatures lower than -100 °C. This novel process, TNCP, is one potential candidate for the commercial production of superior ultra-fine-grained steels in the future.

2014 ◽  
Vol 936 ◽  
pp. 1168-1172 ◽  
Author(s):  
Zhong Ping Chen ◽  
Chao Jian Xiang ◽  
Hua Qing Li

The oxide skin defect during hot rolling process for Cu-Ni-Si alloy strip was investigated. Oxide skin defects were analyzed by means of alloy elements detection and microstructures characterization. The characterization and test results showed that high temperature oxidation and silicon segregation are the main causes of the oxide skin defect. Pilot scale tests indicated that hot processing temperature for C70250 alloy should be lower than 950°C. Reducing atmosphere is recommended during the thermal treatment of Cu-Ni-Si alloys.


2011 ◽  
Vol 291-294 ◽  
pp. 137-140
Author(s):  
Yao Min Zhu ◽  
Qiu Ran Gao ◽  
Feng Zhang Ren ◽  
Shi Jie Fang

The effects of the hot-rolling process on microstructures and strength were investigated for two kinds of magnesium alloy Mg-Zn-Y and Mg-Zn-Y-Nd. In comparison with the as-cast alloys, the tensile strength of Mg-Zn-Y and Mg-Zn-Y-Nd both increases 45%, whereas their elongation decreases 73%, 60% via hot-rolling process, respectively. The results show that the dynamic recrystallization process and the pining effect of I-phase during hot rolling contribute to the fine-grained structure formation. The hot-rolling process has refined the grain size greatly.


2012 ◽  
Vol 6 (6) ◽  
pp. 802-808 ◽  
Author(s):  
Takafumi Komatsu ◽  
◽  
Hitoshi Kobayashi ◽  
Shiro Torizuka ◽  
Shin-ichi Nagayama ◽  
...  

Ultra fine grained steels have been developed by many researchers. However, studies on the effects of different grain size on processes and product functions have been limited because the size of the bulk material has been small for these products. The authors have developed a production process for thin ultra fine grained stainless steel coil, and the effects have been clarified. This paper first reports the effects onmicro hole piercing by comparing materials with different grain sizes. Secondly, orifices are produced from these materials, and the liquid flow volume is measured as the functional effect of different grain sizes.


2012 ◽  
Vol 735 ◽  
pp. 289-294 ◽  
Author(s):  
Toshiaki Manaka ◽  
Goroh Itoh ◽  
Nguyen The Loc ◽  
Yoshinobu Motohashi ◽  
Takaaki Sakuma

The Zn-22Al alloy with fine-equi-axed has been well known as a typical superplastic metallic material [1]. In the present study, The Zn-22Al alloy ingot of 20mm thickness was homogenized, either air-cooled or water-quenched, and then hot-rolled to a thickness of 2mm. Microstractural observation, showed that in the air-cooled specimens lammellar microstructure was formed after homogenization, and become fragmented to fine-grained microstructure as the hot rolling process proceeded. In the water-quenched specimens, equi-axed fine-grained microstructure with grain size under 2.1μm was attained and maintained throughout the hot rolling process.


Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1149
Author(s):  
Yun Dai ◽  
Zhonghan Zhang ◽  
Xibin Wang ◽  
Zhuowei Lu ◽  
Huamin Kou ◽  
...  

Scintillation single crystal fibers (SCFs) have great potential applications in the new generation of high-energy ray and particle detectors due to their morphological advantages. In this work; Ce:LuAG SCFs with a diameter of 1 mm were grown along the direction of [111] by laser-heated pedestal growth (LHPG) method using a transparent ceramic as the source rod; and a doping concentration was 0.1 at%, 0.3 at%, 1 at%, respectively. The effects of growth rate and annealing in air on the scintillation and optical properties of SCF are discussed in detail. The results of analyzing the absorption spectra; radioluminescence (RL) spectra; pulse-height spectra and fluorescence lifetime of SCFs show that the SCF maintains excellent scintillation performance while having a fiber structure. Therefore; Ce:LuAG SCF is a potential candidate material for detector.


2010 ◽  
Vol 3 (1) ◽  
pp. 65-71
Author(s):  
Armindo Guerrero ◽  
Javier Belzunce ◽  
Covadonga Betegon ◽  
Julio Jorge ◽  
Francisco J. Vigil

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1762
Author(s):  
Artur Maciej ◽  
Natalia Łatanik ◽  
Maciej Sowa ◽  
Izabela Matuła ◽  
Wojciech Simka

One method of creating a brass coating is through electrodeposition, which is most often completed in cyanide galvanic baths. Due to their toxicity, many investigations focused on the development of more environmentally friendly alternatives. The purpose of the study was to explore a new generation of non-aqueous cyanide-free baths based on 1-ethyl-3-methylimidazolium acetate ionic liquids. The study involved the formation of copper, zinc, and brass coatings. The influence of the bath composition, cathodic current density, and temperature was determined. The obtained coatings were characterized in terms of their morphology, chemical composition, phase composition, roughness, and corrosion resistance. It was found that the structure of the obtained coatings is strongly dependent on the process parameters. The three main structure types observed were as follows: fine-grained, porous, and olive-like. To the best knowledge of the authors, it is the first time the olive-like structure was observed in the case of an electrodeposited coating. The Cu-Zn coatings consisted of 19–96 at. % copper and exhibited relatively good corrosion resistance. A significant improvement of corrosion properties was found in the case of copper and brass coatings with the olive-like structure.


Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 569
Author(s):  
Ana Claudia González-Castillo ◽  
José de Jesús Cruz-Rivera ◽  
Mitsuo Osvaldo Ramos-Azpeitia ◽  
Pedro Garnica-González ◽  
Carlos Gamaliel Garay-Reyes ◽  
...  

Computational simulation has become more important in the design of thermomechanical processing since it allows the optimization of associated parameters such as temperature, stresses, strains and phase transformations. This work presents the results of the three-dimensional Finite Element Method (FEM) simulation of the hot rolling process of a medium Mn steel using DEFORM-3D software. Temperature and effective strain distribution in the surface and center of the sheet were analyzed for different rolling passes; also the change in damage factor was evaluated. According to the hot rolling simulation results, experimental hot rolling parameters were established in order to obtain the desired microstructure avoiding the presence of ferrite precipitation during the process. The microstructural characterization of the hot rolled steel was carried out using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the phases present in the steel after hot rolling are austenite and α′-martensite. Additionally, to understand the mechanical behavior, tensile tests were performed and concluded that this new steel can be catalogued in the third automotive generation.


Author(s):  
Reza Masoudi Nejad ◽  
Peyman Noroozian Rizi ◽  
Maedeh Sadat Zoei ◽  
Karim Aliakbari ◽  
Hossein Ghasemi

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 3044 ◽  
Author(s):  
Junfeng Shi ◽  
Yifan Ma ◽  
Jing Zhu ◽  
Yuanxin Chen ◽  
Yating Sun ◽  
...  

Intracellular delivery is a critical step in biological discoveries and has been widely utilized in biomedical research. A variety of molecular tools have been developed for cell-based gene therapies, including FDA approved CAR-T immunotherapy, iPSC, cell reprogramming and gene editing. Despite the inspiring results of these applications, intracellular delivery of foreign molecules including nucleic acids and proteins remains challenging. Efficient yet non-invasive delivery of biomolecules in a high-throughput manner has thus long fascinates the scientific community. As one of the most popular non-viral technologies for cell transfection, electroporation has gone through enormous development with the assist of nanotechnology and microfabrication. Emergence of miniatured electroporation system brought up many merits over the weakness of traditional electroporation system, including precise dose control and high cell viability. These new generation of electroporation systems are of considerable importance to expand the biological applications of intracellular delivery, bypassing the potential safety issue of viral vectors. In this review, we will go over the recent progresses in the electroporation-based intracellular delivery and several potential applications of cutting-edge research on the miniatured electroporation, including gene therapy, cellular reprogramming and intracellular probe.


Sign in / Sign up

Export Citation Format

Share Document