scholarly journals Bonding evolution with sintering temperature in low alloyed steels with chromium

2009 ◽  
Vol 41 (2) ◽  
pp. 161-173 ◽  
Author(s):  
L. Fuentes-Pacheco ◽  
M. Campos
Keyword(s):  
Carbothermic Reduction ◽  
High Performance ◽  
Sintering Temperature ◽  
Surface Oxide ◽  
Dew Point ◽  
Processing Route ◽  
Initial Surface ◽  
Sintered Steels ◽  
Controlling Mechanism ◽  
Die Compaction

At present, high performance PM steels for automotive applications follow a processing route that comprises die compaction of water-atomized powder, followed by sintering and secondary treatments, and finishing operations. This study examines Cr-alloyed sintered steels with two level of alloying. In chromium-alloyed steels, the surface oxide on the powder is of critical importance for developing the bonding between the particles during sintering. Reduction of this oxide depends mainly on three factors: temperature, dew point of the atmosphere, and carbothermic reduction provided by the added graphite. The transformation of the initial surface oxide evolves sequence as temperature increases during sintering, depending on the oxide composition. Carbothermic reduction is supposed to be the controlling mechanism, even when sintering in hydrogen-containing atmospheres. The effect of carbothermic reduction can be monitored by investigating the behavior of the specimens under tensile testing, and studying the resultant fracture surfaces.

Robustness versus Performance Assessment for Different Gamma-TiAl Processing Routes

2011 ◽  
Vol 1295 ◽  
Author(s):  
Marc Thomas
Keyword(s):  
High Performance ◽  
Cost Effective ◽  
Processing Route ◽  
Transportation Industry ◽  
Tial Alloys ◽  
Alternative Processing ◽  
Aerospace Applications ◽  
Robust Processing ◽  
Processing Techniques ◽  
Robust Process

ABSTRACTOne of the main driving force for the development of advanced structural materials is weight saving especially in the transportation industry in order to reduce CO2 emission. The utilization of gamma aluminides, as good candidates for aerospace applications, is strongly related to the development of a cost-effective and robust processing route, as far as possible. It is well established that the processing route, i.e. cast, wrought or PM, has a dramatic effect on the microstructure and texture of gamma-TiAl alloys. Therefore, significant microstructural variations through post-heat treatments coupled with compositional modifications can only guarantee a proper balance of desired properties. However, a number of metallurgical factors during the processing steps can contribute to some scattering in properties. This review will highlight several critical process variables in terms of the resulting g-TiAl microstructures. Of primary importance is the as-cast texture which is difficult to control and may contribute to prefer some alternative processing routes to ensure a better repeatability in mechanical results. Some innovative processing techniques for controlling the structure will then be presented. The main point which will be discussed in this paper is whether an approach leading to a robust process would not be at the expense of the high performance of the structural material.

Enabling high performance lithium storage in aluminum: The double edged surface oxide

Nano Energy ◽  
2017 ◽  
Vol 41 ◽  
pp. 731-737 ◽  
Author(s):  
Xinghua Chang ◽  
Zewei Xie ◽  
Zhiliang Liu ◽  
Xinyao Zheng ◽  
Jie Zheng ◽  
...  
Keyword(s):  
High Performance ◽  
Surface Oxide ◽  
Lithium Storage

scholarly journals Development of High-Performance SiCp/Al-Si Composites by Equal Channel Angular Pressing

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 738 ◽  
Author(s):  
Qiong Xu ◽  
Aibin Ma ◽  
Junjie Wang ◽  
Jiapeng Sun ◽  
Jinghua Jiang ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Equal Channel Angular Pressing ◽  
High Performance ◽  
Adhesive Wear ◽  
Processing Route ◽  
Matrix Composites ◽  
New Approach ◽  
Angular Pressing ◽  
The Matrix ◽  
Industry Applications

Relatively low compactness and unsatisfactory uniformity of reinforced particles severely restrict the performance and widespread industry applications of the powder metallurgy (PM) metal matrix composites (MMCs). Here, we developed a combined processing route of PM and equal channel angular pressing (ECAP) to enhance the mechanical properties and wear resistance of the SiCp/Al-Si composite. The results indicate that ECAP significantly refined the matrix grains, eliminated pores and promoted the uniformity of the reinforcement particles. After 8p-ECAP, the SiCp/Al-Si composite consisted of ultrafine Al matrix grains (600 nm) modified by uniformly-dispersed Si and SiCp particles, and the composite relative density approached 100%. The hardness and wear resistance of the 8p-ECAP SiCp/Al-Si composite were markedly improved compared to the PM composite. More ECAP passes continued a trend of improvement for the wear resistance and hardness. Moreover, while abrasion and delamination dominated the wear of PM composites, less severe adhesive wear and fatigue mechanisms played more important roles in the wear of PM-ECAP composites. This study demonstrates a new approach to designing wear-resistant Al-MMCs and is readily applicable to other Al-MMCs.

scholarly journals Enhanced Performance of Fly Ash-Based Supports for Low-Cost Ceramic Membranes with the Addition of Bauxite

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 711
Author(s):  
Wan Fan ◽  
Dong Zou ◽  
Jingrui Xu ◽  
Xianfu Chen ◽  
Minghui Qiu ◽  
...  
Keyword(s):  
Fly Ash ◽  
High Performance ◽  
Bending Strength ◽  
Ceramic Membrane ◽  
Sintering Temperature ◽  
Low Cost ◽  
Pure Water ◽  
Ceramic Membranes ◽  
Mullite Phase ◽  
Optimum Balance

Support is a necessary foundation for ceramic membranes to achieve high performance. Finding the optimum balance between high performance and low cost is still a significant challenge in the fabrication of ceramic supports. In this study, low-cost fly ash-based ceramic supports with enhanced performance were prepared by the addition of bauxite. The pore structure, mechanical strength, and shrinkage of fly ash/bauxite supports could be tuned by optimizing the bauxite content and sintering temperature. When the sintering temperature and bauxite content were controlled at 1300 °C and 40 wt%, respectively, the obtained membrane supports exhibited a high pure water permeance of approximately 5.36 m3·m−2·h−1·bar−1 and a high bending strength of approximately 69.6 MPa. At the same time, the optimized ceramic supports presented a typical mullite phase and excellent resistance to acid and alkali. This work provides a potential route for the preparation of ceramic membrane supports with characteristics of low cost and high performance.

Prelithiated Surface Oxide Layer Enabled High-Performance Si Anode for Lithium Storage

2019 ◽  
Vol 11 (20) ◽  
pp. 18305-18312 ◽  
Author(s):  
Yuanchao Zhu ◽  
Wei Hu ◽  
Jianbin Zhou ◽  
Wenlong Cai ◽  
Yue Lu ◽  
...  
Keyword(s):  
Oxide Layer ◽  
High Performance ◽  
Surface Oxide ◽  
Surface Oxide Layer ◽  
Lithium Storage ◽  
Si Anode

Evaluation of the Sinterability of Copper-Substituted Ferrites by Means of Dilatometric Thermal Analysis

2014 ◽  
Vol 805 ◽  
pp. 254-259
Author(s):  
Vera Lúcia Othéro de Brito ◽  
Stéphanie Alá Cunha ◽  
Ana Paula Ribeiro Uchoas ◽  
Fabiana Faria de Araújo ◽  
Cristina Bormio Nunes ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Solid State ◽  
Sintering Temperature ◽  
Thermal Analyses ◽  
Spinel Ferrites ◽  
Solid State Reactions ◽  
Processing Route ◽  
Ceramic Method ◽  
Spinel Formation ◽  
Made In

Cobalt and cobalt-manganese spinel ferrites have magnetostrictive properties suitable for application in magneto-electric and magneto-mechanical transducers. In this work, copper-substituted ferrites of these compositions were processed by means of the ceramic method and their sinterabilities were evaluated by dilatometric thermal analyses. The results obtained suggest that copper affects the solid-state reactions for the spinel formation and lowers the required sintering temperature for the ferrites. However, the densification obtained with sintering of the copper-substituted ferrites at 950oC for 6h was only 64%, which indicates that further adjustments on the processing route must be made in order to obtain higher densities.

scholarly journals Architectured ZnO–Cu particles for facile manufacturing of integrated Li-ion electrodes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Fabio L. Bargardi ◽  
Juliette Billaud ◽  
Claire Villevieille ◽  
Florian Bouville ◽  
André R. Studart
Keyword(s):  
Metal Ion ◽  
High Performance ◽  
Mechanical Stability ◽  
Active Material ◽  
Processing Route ◽  
Zno Films ◽  
Charge Capacity ◽  
Zno Powders ◽  
Polymeric Binders ◽  
Li Ion

Abstract Designing electrodes with tailored architecture is an efficient mean to enhance the performance of metal-ion batteries by minimizing electronic and ionic transport limitations and increasing the fraction of active material in the electrode. However, the fabrication of architectured electrodes often involves multiple laborious steps that are not directly scalable to current manufacturing platforms. Here, we propose a processing route in which Cu-coated ZnO powders are directly shaped into architectured electrodes using a simple uniaxial pressing step. Uniaxial pressing leads to a percolating Cu phase with enhanced electrical conductivity between the active ZnO particles and improved mechanical stability, thus dispensing the use of carbon-based additives and polymeric binders in the electrode composition. The additive-free percolating copper network obtained upon pressing leads to highly loaded integrated anodes displaying volumetric charge capacity 6–10 fold higher than Cu-free ZnO films and that matches the electrochemical performance reported for advanced cathode structures. Achieving this high charge capacity using a readily available pressing tool makes this approach a promising route for the facile manufacturing of high-performance electrodes at large industrial scales.

Effect of High Temperature Process on Microstructure and Properties of Industrial Steel Slag Cement

2019 ◽  
Vol 814 ◽  
pp. 413-418
Author(s):  
Fang Wang ◽  
Ming Han Xu ◽  
Rui Hua Wang ◽  
Chao Yang ◽  
Ai Xia Chen ◽  
...  
Keyword(s):  
Steel Industry ◽  
High Performance ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Steel Slag ◽  
Holding Time ◽  
Raw Material ◽  
Experimental Comparison ◽  
Slag Cement ◽  
Actual Performance

The construction industry continues to develop and the requirements for cement performance are getting higher and higher. At the same time, in the steel industry, the discharge of steel slag is also increasing. The effective reuse of steel slag has become a prominent problem in the steel industry. . Therefore, it is envisaged to use steel slag as a raw material for the cement production process to produce cement and to produce high-performance cement. The main raw materials of this experiment are steel slag, limestone, sandstone and shale. Through the cement preparation process, the cement is made, and then the cement is made into concrete to test its performance. This experiment mainly studies the sintering temperature and holding time variable. In the experimental test, the analysis and comparison were carried out in five aspects of the degree of macroscopic cracking, particle size, density, microstructure and composition. In the comparison experiment of sintering temperature, with the increase of temperature, the flexural and compressive properties of cement gradually increased. In this test, 1200 °C is the most suitable temperature for the performance of the cement. Through the experimental comparison of different holding time, it is known that with the prolonging of the holding time, the microstructure and actual performance of the cement are continuously enhanced. Comprehensive consideration: the ratio of steel slag in cement ratio is 10%, sintering temperature is 1200 °C, and heat preservation is 2h. The steel slag cement prepared under this condition has the strongest performance.

scholarly journals Zinc Binding by Histatin 5 Promotes Fungicidal Membrane Disruption in C. albicans and C. glabrata

2020 ◽  
Vol 6 (3) ◽  
pp. 124 ◽  
Author(s):  
Hannah L. Norris ◽  
Rohitashw Kumar ◽  
Chih Yean Ong ◽  
Ding Xu ◽  
Mira Edgerton
Keyword(s):  
High Performance ◽  
Opportunistic Pathogen ◽  
Human Saliva ◽  
Membrane Disruption ◽  
Initial Surface ◽  
Surface Binding ◽  
Histatin 5 ◽  
Peptide Assembly ◽  
Cell Association ◽  
Exciting Potential

Histatin 5 (Hst 5) is an antimicrobial peptide produced in human saliva with antifungal activity for opportunistic pathogen Candida albicans. Hst 5 binds to multiple cations including dimerization-inducing zinc (Zn2+), although the function of this capability is incompletely understood. Hst 5 is taken up by C. albicans and acts on intracellular targets under metal-free conditions; however, Zn2+ is abundant in saliva and may functionally affect Hst 5. We hypothesized that Zn2+ binding would induce membrane-disrupting pores through dimerization. Through the use of Hst 5 and two derivatives, P113 (AA 4-15 of Hst 5) and Hst 5ΔMB (AA 1-3 and 15-19 mutated to Glu), we determined that Zn2+ significantly increases killing activity of Hst 5 and P113 for both C. albicans and Candida glabrata. Cell association assays determined that Zn2+ did not impact initial surface binding by the peptides, but Zn2+ did decrease cell association due to active peptide uptake. ATP efflux assays with Zn2+ suggested rapid membrane permeabilization by Hst 5 and P113 and that Zn2+ affinity correlates to higher membrane disruption ability. High-performance liquid chromatography (HPLC) showed that the higher relative Zn2+ affinity of Hst 5 likely promotes dimerization. Together, these results suggest peptide assembly into fungicidal pore structures in the presence of Zn2+, representing a novel mechanism of action that has exciting potential to expand the list of Hst 5-susceptible pathogens.

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